ArticleLiterature Review

Use of amino acids as growth hormone-releasing agents by athletes

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Abstract

Specific amino acids, such as arginine, lysine and ornithine, can stimulate growth hormone (GH) release when infused intravenously or administered orally. Many individuals consume amino acids before strength training workouts, believing this practice accentuates the exercise-induced GH release, thereby promoting greater gains in muscle mass and strength. The GH response to amino acid administration has a high degree of interindividual variability and may be altered by training status, sex, age, and diet. Although parenteral administration consistently leads to increased circulating GH concentration, oral doses that are great enough to induce significant GH release are likely to cause stomach discomfort and diarrhea. During exercise, intensity is a major determinant of GH release. Although one study showed that arginine infusion can heighten the GH response to exercise, no studies found that pre-exercise oral amino acid supplementation augments GH release. Further, no appropriately conducted scientific studies found that oral supplementation with amino acids, which are capable of inducing GH release, before strength training increases muscle mass and strength to a greater extent than strength training alone. The use of specific amino acids to stimulate GH release by athletes is not recommended.

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... No entanto, não existem estudos que comprovem a eficácia dessa prática. A resposta do GH à administração de aminoácidos apresenta variabilidade individual, sendo alterada pela intensidade da atividade (maior liberação de GH quando o treinamento é mais intenso), sexo (menor resposta em homens), dieta (resposta menor nos que consomem muita proteína) e via de administração (a dose oral necessária para aumentar a liberação de GH geralmente causa desconforto estomacal e diarréia) (31) . Além disso, os níveis circulantes de IGF-1 não são alterados após a administração oral de arginina e lisina (31) . ...
... A resposta do GH à administração de aminoácidos apresenta variabilidade individual, sendo alterada pela intensidade da atividade (maior liberação de GH quando o treinamento é mais intenso), sexo (menor resposta em homens), dieta (resposta menor nos que consomem muita proteína) e via de administração (a dose oral necessária para aumentar a liberação de GH geralmente causa desconforto estomacal e diarréia) (31) . Além disso, os níveis circulantes de IGF-1 não são alterados após a administração oral de arginina e lisina (31) . Portanto, o uso de aminoácidos específicos como estimuladores para a liberação de GH com o intuito de aumentar o ganho de massa e força muscular ou alterar a composição corporal não é recomendado. ...
... Não parece haver dúvidas de que as diferentes estaturas observadas em participantes de determinados esportes deve-se a apenas um viés de seleção e não ao tipo de esporte praticado (11,(22)(23)(24)28) . Tanto a restrição dietética quanto o uso indiscriminado de suplementos alimentares ou substâncias ergogênicas são prejudiciais para crianças e adolescentes envolvidos em atividades físicodesportivas (11,23,31,32) . ...
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OBJETIVO: Apresentar revisão atualizada e crítica sobre o impacto do esporte e da atividade física no crescimento, desenvolvimento puberal e mineralização óssea de crianças e adolescentes. FONTES DE DADOS: Pesquisa bibliográfica nos bancos de dados Medline e Lilacs (1987-2007), selecionando os artigos escritos em inglês, português ou espanhol, a partir dos descritores "esportes" e "exercícios", em combinação com "crescimento", "puberdade" e "mineralização óssea". Foram examinados 252 artigos e 48 deles selecionados. SÍNTESE DOS DADOS: Diferentes modalidades esportivas não aumentam ou diminuem a estatura. Ocorre um viés de seleção, no qual fatores constitucionais determinam a seleção de biótipos privilegiados para determinados esportes. O exercício físico leve a moderado estimula o crescimento e deve ser incentivado. A atividade física extenuante, principalmente quando associada à restrição dietética, afeta o crescimento, o desenvolvimento puberal, a função reprodutiva e a mineralização óssea. A musculação praticada por jovens pré-púberes pode ser prejudicial, se não for realizada sob supervisão, já que há um potencial risco de lesão na cartilagem de crescimento. Entretanto, quando bem supervisionada, pode levar a um aumento de força e resistência muscular. CONCLUSÕES: Os efeitos deletérios dos esportes sobre o crescimento e desenvolvimento só foram observados em atletas de elite submetidos a treinamento intensivo e restrição alimentar. Alterações hormonais e de citocinas inflamatórias são parte da fisiopatologia desse processo. É necessário que estudos longitudinais avaliem as repercussões da atividade física recreacional sobre a estatura final.
... Alternatively, HGH levels in the body can potentially be increased by stimulation of endogenous secretion by nutritional supplements, particularly those based on amino acids. The amino acids arginine, methionine, phenylalanine, lysine, and histidine have been shown to promote HGH secretion in adults (Knopf et al. 1965;Chromiak and Antonio 2002). However, studies investigating the effect of amino acid supplementation on HGH levels show conflicting results (Andreassen 2010;de Lemos and Vigen 2014). ...
... However, studies investigating the effect of amino acid supplementation on HGH levels show conflicting results (Andreassen 2010;de Lemos and Vigen 2014). Greater and more consistent increases in HGH concentrations after amino acid consumption were found in women as compared to men (Chromiak and Antonio 2002). Therefore, in this study we aimed to investigate the effect of nutritional supplementation with a meal replacement beverage (Ensure Active Heart Health) or an amino acid beverage containing essential amino acids plus citrulline and carnitine designed for stimulation of muscle function in heart failure (AA drink) on HGH production in elderly women with heart failure. ...
... In this randomized intervention study, ingestion of the meal replacement drink significantly increased plasma HGH concentration in elderly women with heart failure, while an amino acid drink designed to stimulate an anabolic response in skeletal muscle did not result in an increase in plasma HGH. Plasma arginine and lysine concentrations, the two amino acids thought to be the most potent stimulators of HGH release (Chromiak and Antonio 2002), were significantly higher after consumption of the AA drink compared to the meal replacement drink. HGH is secreted from the pituitary gland in a pulsatile manner and exerts its effect either directly or indirectly on the heart by stimulating the production of the somatomedin insulin-like growth factor-1 (IGF-1), which promotes anabolic metabolism (Anker et al. 2001;Cicoira et al. 2003;Colao 2008). ...
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Growth hormone treatment has gained attention over the past decade as a treatment for heart failure. Human growth hormone (HGH) must be administered by injections (usually daily), so there is considerable advantage to stimulation of endogenous secretion by amino acid-based nutritional supplementation. However, studies investigating the effect of amino acid (AA) supplementation show conflicting results. Therefore, in this study we aimed to investigate the effect of nutritional supplementation on HGH production in elderly women with heart failure. Eight elderly women with heart failure participated in this randomized cross-over study. Plasma HGH concentration was measured before and for 4 h following ingestion of a mixture of protein, carbohydrate, and fat or an AA beverage. HGH concentration was determined with ELISA kits and AA concentrations were analyzed by Liquid Chromatography–Mass Spectrometry (LCMS). Linear mixed models was performed to analyze the effect of time, treatment, and interaction. Plasma arginine and lysine concentrations were significantly higher after consumption of the AA drink compared to the mixture of protein, carbohydrate, and fat. Nonetheless, only ingestion of the protein, carbohydrate, and fat mixture (meal replacement) increased HGH concentration. HGH concentration was increased in elderly women with heart failure following consumption of a meal replacement containing protein, carbohydrate, and fat. Consumption of a mixture of amino acids failed to increase HGH concentration despite significantly greater elevations in plasma amino acid concentrations, including arginine and lysine. The stimulatory effect of the protein/carbohydrate/fat mixture was presumably mediated by factors other than increases in free amino acid concentrations.
... Concerns over food security have existed throughout history. The final report of the 1996 World Food Summit states that food security exists when all people, at all times, have physical and economic access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life "Raj [4,55]. Household food security exists when all members, at all times, have access to enough food for an active, healthy life [56]. ...
... Organization of the United Nations (FAO) called the summit in response to widespread under-nutrition and growing concern about the capacity of agriculture to meet future food needs. The conference produced two key documents, the Rome Declaration on World Food Security and the World Food Summit Plan of Action [55,61]. ...
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Sorghum is the major food in Sudanese specially among poorer people, of low nutritional value; to achieve all the nutritional balance. While there are a highly nutritive value pods such like soybean, which contains high protein, fats and essential amino acids that important for human health. Nevertheless wheat has a physical improvement on sorghum cooked products. Moreover, there are many studies in and abroad investigating the nutritional value of soy and sorghum but the fortification is still below the needs. There this is a conceptual study to modify the previous technologies to safe foods by introducing rural technology considering all the production selectors such as; rural agricultural production, rural technology adaptation, rural processing and fortification. The produced fortified sorghum with wheat, soy bean with former fortification additives aimed to safe food and health by modifying local foods in rural and urban areas for pregnancies, infants, children and adults. It based on that presence of a bulk of food materials and capability to produce others, ability to formulate nutritive food and their production technology can access development of food security in rural areas. The methodology depends on the information's obtained from historical literature, historical surveys, proposed proper expected technology for fortification components through basal food quality control of sorghum production, soybean current and future production, technology transfer and adaptability of processing machines, screening and biometrical scientific researches, fortification expecting nutritional balance. Designing of local made machines for milling, boiling, roasting and packaging by transfer of technology and innovation adopted. Formulation of fortified sorghum. Also rural processing technology formulated. The analyzed results of literature, screening tests, survey and scientific results showed that rural production of soybean adaption can well be succeeded, rural manufacturing of the basic and fortified nutritional components can be done, systematic researches on some Sudanese diet such as fortified cooked sorghum soft sheets (Kisra), fortified thin porridge (Madeda), fortified thick porridge (Logma or Asida) with good protein, fats, minerals and fatty acids can be easily adopted. We come to conclude that the adaptation of fortified sorghum technology can be to produce different fortified sorghum products for different kinds of peoples; adults, children, infants and pregnancies. And the theories gave positive results through the analysis of different fortification components through simple technology. Finally tactics and strategies were designated for sorghum fortification.
... To enhance performance, athletes are already using arginine (known as a potent hormone secretagogue) supplementation, in an attempt to stimulate GH levels, and, subsequently, potentiate IGF-1, thus, increasing muscle mass [28,53]. In fact, GH response to amino acids is affected by sex and training status and repercussions on exercise-induced GH response will be slight [54]. Even though GH release during aerobic exercise is clearly related to exercise intensity and duration, the use of specific amino acids for the purpose of stimulating GH release to promote greater gains in muscle mass and strength and to alter body composition is not recommended [54]. ...
... In fact, GH response to amino acids is affected by sex and training status and repercussions on exercise-induced GH response will be slight [54]. Even though GH release during aerobic exercise is clearly related to exercise intensity and duration, the use of specific amino acids for the purpose of stimulating GH release to promote greater gains in muscle mass and strength and to alter body composition is not recommended [54]. ...
Article
Dietary nitrates and L-Arginine have been increasingly recognized to play a promising role as sport dietary supplementation, getting more and more popular as ergogenic aids, namely, substances used with regard to performance enhancement. Inorganic nitrate (NO3-) is abundant in numerous foodstuffs and is convertible into nitrite (NO2-) following ingestion. Nitrite, in turn, can be metabolized into nitric oxide (NO), one of the most widespread signaling molecules, taking part in virtually every cellular and organic functions, most notably blood flow regulation and vasodilation, mitochondrial respiration, platelet function and metabolic homeostasis. L-Arginine is a conditionally essential amino acid that has been target of considerable attention as the main precursor of NO, revealing other promising potential effects on growth hormone (GH) release, promotion of creatine synthesis, all leading to possible exercise tolerance and muscle efficiency benefits, impairment of O2 uptake (cost of submaximal exercise) and rise in workout duration before fatigue. Accordingly, the purpose of this review is to provide an overview on the accumulating evidence concerning not only the importance of NO and its associated precursors in exercise and sports performance, but also the inherent cardiovascular modulation during workout, as well as ascertain the possible benefits and hazards, never despising the crucial role ascribed to sports nutrition professionals.
... Thus, in potassium deficient animals both basal GH levels and GH response to GRF are reduced, this deficiency being corrected after potassium repletion (Flyvbjerg et al. 1991;Gil-Peña et al. 2010). In addition, potassium infusion to healthy man increases GH in plasma (Dluhy et al. 1972), and increased serum potassium and GH release have been observed after infusion of cationic amino acids or after physical exercises (Merimee et al. 1965;Hertz and Richardson 1972;Bushinsky and Gennari 1978;Massara et al. 1979;Williams et al. 1985;Bucci et al. 1990;Chromiak and Antonio 2002;Kanaley 2008;Denura et al. 2010). ...
... It is then conceivable that the alteration of potassium levels may be dependent on the rate of basic amino acid increase in plasma. In the last decades, the use of amino acids such as l-arginine, l-lysine or l-ornithine by many athletes, in order to rise growth hormone, has notably increased (Isidori et al. 1981;Bucci et al. 1990;Chromiak and Antonio 2002;Denura et al. 2010). In some cases, acute pancreatitis was observed as another hazardous effect of l-arginine supplementation (Saka et al. 2004).The possible implication of potassium changes in the pancreatic alterations observed after cationic amino acid supplementation has not been explored. ...
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The administration of l-arginine hydrochloride has been used for testing pituitary secretion in humans, and as an experimental model for induction of acute pancreatitis in rats and mice. Whereas in the first case, the administration of the amino acid is associated with hiperkalemia, in the model of acute pancreatitis no data are available on possible changes in potassium homeostasis. The present study shows that the acute administration to mice of l-arginine hydrochloride or other cationic amino acids almost duplicate plasma potassium levels. This effect was associated to a marked decrease of tissue potassium in both pancreas and liver. No changes were found in other tissues. These changes cannot be ascribed to the large load of chloride ions, since similar effects were produced when l-ornithine aspartate was administered. The changes in potassium levels were dependent on the dose. The displacement of intracellular potassium from the liver and pancreas to the extracellular compartment appears to be dependent on the entry of the cationic amino acid, since the administration of an equivalent dose of alfa-difluoromethyl ornithine HCl (DFMO), a non physiological analog of l-ornithine, which is poorly taken by the tissues in comparison with the physiological cationic amino acids, did not produce any change in potassium levels in pancreas and liver. The analyses of the expression of cationic amino acid transporters (CAT) suggest that the CAT-2 transporter may be implicated in the potassium/cationic amino acid interchange in liver and pancreas. The possible physiological or pathological relevance of these findings is discussed.
... These patients are given special diets, restricting the intake of these AA, and are supplemented with all the other AA (Dashman & Sansaricq 1993, Levy 1989. Another, non-clinical, application of AA supplementation was developed for an increasing number of sporting requirements, mainly in order to gain muscle growth (Rubinstein & Federman 2000, Chromiak & Antonio 2002. ...
... In contrast to the insulin peak, which was very homogenous in the volunteers of the AA group, the hGH release showed a higher individual variability. This indicates that personal response may be based on factors such as age, individual food preferences or training status, as described by Chromiak & Antonio (2002). However, a highly significant hGH release was observed in all of the members of the AA group, which correlated well with previously published data (Muggeo et al. 1975, Cameron et al. 1988, Lundeberg et al. 1991). ...
Article
The response of insulin, human growth hormone (hGH), cortisol, leptin and ghrelin, in addition to various metabolic parameters, was measured at 10 minute intervals following the oral ingestion of a standardised physiological dose of essential amino acids (AA). Twenty-eight healthy male, fasted volunteers (aged 18–40 yrs, BMI 18·0– 24·5 kg/m 2 ) took part in the study; 13 volunteers in the AA group, nine subjects in an iso-caloric control group, and a further six subjects served as fasting controls. Twenty minutes after ingestion, insulin reached peak concentrations that were up to 500% higher than basal values (P,0·0001). The AA group and iso-caloric control group showed a similar insulin response. AA ingestion led to an increase in hGH secretion with maximum concentrations being 21001013% higher than the basal values (P,0·0001). In contrast, no changes in hGH concentrations were observed in the iso-caloric controls; in the fasting controls only a slight increase in hGH was found towards the end of the fasting period. While cortisol decreased significantly (P,0·01) during the study in the AA group, neither control group showed a significant change in this parameter. Changes in leptin levels remained insignificant in all three groups, whereas ghrelin showed a different profile in each of the three groups, i.e. a continuous rise towards the end of the study period (P,0·001) in the AA group, a less significant effect for the fasting group, and no effect at all in the iso-caloric control group. There was no significant correlation between the concentrations or the area under curve of the hormones measured in any of the groups. The endocrine data provided in this study indicate that a single bolus of essential AA in fasted individuals is associated with both anabolic and catabolic hormonal responses.
... Concerns over food security have existed throughout history. The final report of the 1996 World Food Summit states that food security exists when all people, at all times, have physical and economic access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life "Raj [4,55]. Household food security exists when all members, at all times, have access to enough food for an active, healthy life [56]. ...
... Organization of the United Nations (FAO) called the summit in response to widespread under-nutrition and growing concern about the capacity of agriculture to meet future food needs. The conference produced two key documents, the Rome Declaration on World Food Security and the World Food Summit Plan of Action [55,61]. ...
... Intravenous administration of various AAs can stimulate GH secretion [133,134]. In detail, basic AAs, such as arginine, histidine, and lysine, elicit a clear rise in GH levels when infused intravenously. ...
... However, the GH response to AA administration may be affected by several factors such as physical training, sex, diet, time since last meal, and age [133]. In healthy young male bodybuilders, serum GH levels were not consistently altered following the ingestion of AA supplements (total 2.4 g of arginine and lysine or 1.85 g of ornithine and tyrosine over a 3-h period after an overnight fast) [143]. ...
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Growth hormone (GH) and insulin-like growth factor-1 (IGF-I) are pleiotropic hormones with important roles in lifespan. They promote growth, anabolic actions, and body maintenance, and in conditions of energy deprivation, favor catabolic feedback mechanisms switching from carbohydrate oxidation to lipolysis, with the aim to preserve protein storages and survival. IGF-I/insulin signaling was also the first one identified in the regulation of lifespan in relation to the nutrient-sensing. Indeed, nutrients are crucial modifiers of the GH/IGF-I axis, and these hormones also regulate the complex orchestration of utilization of nutrients in cell and tissues. The aim of this review is to summarize current knowledge on the reciprocal feedback among the GH/IGF-I axis, macro and micronutrients, and dietary regimens, including caloric restriction. Expanding the depth of information on this topic could open perspectives in nutrition management, prevention, and treatment of GH/IGF-I deficiency or excess during life.
... Thus, methods for increasing endogenous GH secretion and subsequent IGF-1 synthesis by oral intake might be a better alternative. As the oral administration of amino acids (i.e., arginine, glutamine, glycine, and lysine) has been found to increase the release of endogenous GH [16], supplementation with these amino acids might be a beneficial pharmacological intervention. We previously demonstrated that a "GH-releaser diet" significantly attenuated β-amyloid (Aβ) (1-42)-induced memory impairment [17] via stimulation of the hippocampal IGF-1 receptor [18]. ...
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Background It has been recognized that a defect in klotho gene expression accelerates the degeneration of multiple age-sensitive traits. Accumulating evidence indicates that aging is associated with declines in cognitive function and the activity of growth hormone (GH)/insulin-like growth factor-1 (IGF-1). Methods In this study, we examined whether a GH-releaser diet could be effective in protecting against cognitive impairment in klotho mutant mice. Results The GH-releaser diet significantly induced the expression of IGF-1 and IGF-1 receptors in the hippocampus of klotho mutant mice. Klotho mutant mice showed significant memory impairments as compared with wild-type mice. In addition, the klotho mutation significantly decreased the expression of cell survival/antiapoptotic factors, including phospho-Akt (p-Akt)/phospho-glycogen synthase kinase3β (p-GSK3β), phospho-extracellular signal-related kinase (p-ERK), and Bcl-2, but significantly increased those of cell death/proapoptotic factors, such as phospho-c-jun N-terminal kinase (p-JNK), Bax, and cleaved caspase-3 in the hippocampus. Treatment with GH-releaser diet significantly attenuated both decreases in the expression of cell survival/antiapoptotic factors and increases in the expression of cell death/proapoptotic factors in the hippocampus of klotho mutant mice. In addition, klotho mutation-induced oxidative stress was significantly attenuated by the GH-releaser diet. Consequently, a GH-releaser diet significantly improved memory function in the klotho mutant mice. GH-releaser diet-mediated actions were significantly reversed by JB-1, an IGF-1 receptor antagonist. Conclusion The results suggest that a GH-releaser diet attenuates oxidative stress, proapoptotic changes and consequent dysfunction in klotho mutant mice by promoting IGF-1 expression and IGF-1 receptor activation.
... Muitos atletas usam específicos aminoácidos a fim de estimular a secreção de hormônio do crescimento (GH -Growth Hormone), acreditando que esta prática irá promover ganhos significativos de massa e força musculares (CHROMIAK; ANTONIO, 2002). Por mecanismos ainda pouco esclarecidos, supõe-se que a arginina, um aminoácido peptídico, possa agir na produção do fator de crescimento insulina-símile (IGF-1 -insulin-like growth factor), influenciando o sistema do GH, que irá modular as ações da testosterona no músculo esquelético (MAURAS et al, 1998). ...
Article
Embora existam aplicacoes clinicas de esteroides anabolicos androgenicos (EAA), tambem ha abuso generalizado destas drogas por estarem relacionadas ao aumento do tamanho e forca muscular. O uso indevido de EAA, hormonio de crescimento e ergogenicos e um problema complexo, pois conduziu ao abuso destes compostos, a principio por competidores de alto nivel, alcancando tambem areas de atividade fisica em geral. Este trabalho tem por objetivo avaliar o efeito anabolico do EAA e se este efeito sofre influencia de suplementacao alimentar, mesmo em condicoes sedentarias. Utilizou-se ratos WISTAR que foram divididos em quatro grupos. Grupos DECA: receberam tratamento com decanoato de nandrolona (DN), em duas doses semanais de 10 mg. Kg-1 cada; DECAS: receberam a mesma dose de DN e suplementacao alimentar, na dose de 0,86 ml/kg; CON: receberam apenas o veiculo (oleo de amendoim) na mesma dose que DN; CONS: receberam o mesmo volume do veiculo e a mesma dose do suplemento alimentar. Todos os animais foram tratados por 4 semanas. Determinou-se o teor de proteina e lipideo corporais atraves das tecnicas de Kjeldahl e Soxhlet, respectivamente. Os resultados encontrados neste estudo demonstraram aumento da sintese proteica muscular (CON: 17,4% ± 1,344; CONS: 18,6% ± 1,289; DECA: 27,6% ± 0,935; DECAS: 36,4% ± 0,613) e diminuicao do teor de lipideos corporais (CON: 26,1%± 2,460; CONS: 29,1%± 1,027; DECA: 21,8%± 0,701; DECAS: 23,2%± 1,509). Portanto, conclui-se que a suplementacao alimentar utilizada reforca o efeito anabolico do DN por meio de uma acao sinergica no aumento do teor de proteina. 10.5216/ref.v5i1.4621
... O excesso de ingestão proteica pode, ainda, aumentar a produção de ureia, causar cólica abdominal e diarreia e aumentar o risco de desidratação. 40,41 Além disso, como a proteína é a principal fonte de produção ácida endógena através da excreção de sulfato, essa produção aumentada pode influenciar negativamente a densidade mineral óssea, se não for balanceada com uma dieta adequada (frutas e vegetais). 42 Outra substância bastante utilizada pelos usuários de academia foi a creatina, cujo maior percentual encontrado foi de 89%. ...
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Objective: The objective of the present study was to systematically review the prevalence, indicative ways, and adverse effects of ergogenic resources, such as dietary supplements (DS) and anabolic an-drogenic steroids (AAS), that were reported, by bodybuilders in gyms in Brazil. Methods: References search was performed in November 2011 in the Medline, SciELO, BIREME, and Lilacs data basis by the key-words: anabolic-androgenic steroids, nutritional supplements, and gyms. To be included the studies should have investigated the prevalence of the use of ergogenic resources in gyms in Brazil. Ninety-three investigations were selected, but only 18 were included. Results: The highest prevalence of DS consumption was in Belo Horizonte (90.8%), followed by Vitoria (70%), Cascavel (66%) and Curitiba (50.61%). For the AAS use, the highest prevalence was in Belo Horizonte with 85%, followed by Aracaju (31%) and Rio Grande do Sul (24.9%). The products mainly consumed as DS were: derived proteins, amino acids and creatine. The most widely used AAS increase were Deca-Durabolin, Susta-non and Winstrol. Side effects mostly observed by the AAS users were the appearance of acne (46 to 94%) and aggressiveness (47 to 73%). Conclusion: Both the use of DS and AAS are exacerbated in the gyms of Brazil, mainly in the Southeast. In addition, the abuse of AAS is due to a lack of information about their contraindications, resulting in innumerous adverse health effects.
... growth hormone (GH)) in managing patients with catabolic disease states 56 . Specific amino acids, such as arginine, lysine and ornithine, can stimulate GH release when infused intravenously or administered orally 62 . The chronic BCAA effects on plasma levels of GH and plasma levels of GH binding protein might suggest an improvement of muscle activity through protein synthesis 63 . ...
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Background: Normal adults require twenty L-amino acids (AA) for protein synthesis. Functional AA regulate key metabolic pathways that are necessary for maintenance, growth, reproduction and immunity. Dietary supplementation with one or a mixture of these AA may be beneficial for ameliorating health problems at various stages of the life cycle and for optimizing of the efficiency of metabolic transformations. During disease, other amino acids also become essential. The principal goal of protein/amino acid administration in various pathological conditions in intensive care unit (ICU) patients is to provide the precursors of protein synthesis in tissues with high turnover and to protect skeletal muscle mass and function. Amino acid requirements in parenteral nutrition (PN) are higher when the patient is stressed/traumatized/infected than in the unstressed state. In severely ill ICU patients a higher provision of protein and amino acids has been associated with a lower mortality. Methods and results: An overview of the effects and dosage of amino acids in nutritional support of various pathological conditions in ICU patients is presented. Conclusion: It was demonstrated that 2.0-2.5 g protein substrate/kg normal body weight/day is safe and could be optimal for the most critically ill adults to decrease the risk of morbidity and mortality in some pathological conditions.
... Dessa maneira, os aminoácidos que possivelmente estão sendo utilizados para o crescimento muscular e os aumentos de força são a creatina, a arginina, a lisina e a ornitina. Dentre outros aminoácidos essenciais que também podem estar envolvidos na síntese de proteínas e desenvolvimento muscular 11 . E ainda, apesar de ter conhecimento do papel das proteínas e aminoácidos no desenvolvimento de hipertrofia muscular e de força, há ainda uma necessidade em questionar a utilização desse tipo de suplementação adicional 2 . ...
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Averiguar se há o consumo de suplementos entre praticantes de musculação no município de Irati, com ênfase em suplementos com proteína e minoácidos. O estudo foi realizado de maio a novembro de 2009, no município de Irati, estado do Paraná. Participaram do estudo 63 praticantes de musculação, em quatro academias, sendo 39 homens (61,9%) e 24 mulheres (38,1%), com predomínio entre 19 a 27 anos. O instrumento utilizado foi um questionário com 13 perguntas discursivas e objetivas, referente ao objetivo do estudo. Os resultados mais expressivos foram: 39% utilizam algum tipo de suplementos, 84% desse utilizam suplementos com proteínas e aminoácidos, 36,6% fazem controle com o profissional de Educação Física, 36,6% não faz nenhum controle do uso. Conclui-se que o uso de suplementação é significante no grupo analisado, porém são necessários novos estudos sobre o consumo de suplementos e seus efeitos no organismo para garantir maior segurança para aquelas pessoas que utilizam.
... 19 The potential benefits of protein supplementation include increased muscle growth, improved endurance, and enhanced sports performance. [19][20][21] A potential problem with protein supplementation is exceeding the normal dosage. A normal dosage should not surpass 2.0 g/kg/d because no athletic gain is found with high quantity. ...
... Key words: oral supplementation, lipid metabolism, aerobic exercise, growth hormone O hormônio do crescimento (GH) exerce funções anabólicas que promovem o crescimento e hipertrofia muscular pela facilitação do transporte de aminoácidos para o interior das células (Fayh, Friedman, Sapata, & De Oliveira, 2007). Suas principais funções são: fortes efeitos lipolíticos, pois estimula a lipólise através da oxidação de ácidos graxos dos tecidos adiposos durante restrição calórica e no exercício físico pela ação da enzima lipoproteína lipase, promove alterações na composição corporal e reduz o metabolismo dos carboidratos para manter os níveis da glicose sangüínea (Chromiak & Antonio, 2002;Mauras et al., 2000;Moller, Jorgense, Alberti, Flyvbjerg, & Schmitz, 1990;Quisth et al., 2005). ...
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A Suplementação Oral de Arginina (SOA) e o exercício físico são capazes de modificar a secreção do Hormônio de Crescimento (GH), interferindo no metabolismo lipídico. O objetivo do estudo foi verificar o efeito da SOA, do exercício físico aeróbio e a combinação da suplementação com o exercício sobre a secreção de GH e metabolismo lipídico em ratos. A amostra foi composta por 40 ratos machos da linhagem Wistar, divididos em grupos Controle Sedentário (CS), Arginina Sedentário (AS), Controle treinado (CT) e Arginina Treinado (AT). O AS e AT receberam a suplementação oral de arginina em dias alternados e os CT e AT realizaram exercícios de natação por 1 hora/dia com sobrecarga equivalente à 5% do peso corporal 5 dias por semana durante 4 semanas. Em conclusão, os resultados demonstram que o treinamento físico aeróbio não alterou o metabolismo lipídico e diminuiu os valores séricos de GH e a SOA não alterou a concentração de GH em ratos Wistar.
... The alleged effects of L-arginine supplementation on the release of anabolic hormones has stimulated athletes to use this amino acid for promoting greater gains in muscle mass, strength, and performance (12). In the present study, there was no significant difference between groups (ARG and PLA) in the TRT in the two sessions of 5K-TT. ...
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Nutritional supplements based on the amino acid L-arginine have been hypothesized to improve exercise performance by increasing levels of insulin and growth hormone (GH). Changes of these parameters in response to L-arginine supplementation may clarify the mechanisms underlying its putative physiological effects on physical performance. The aim of the study was to evaluate the effect of L-arginine supplementation on serum insulin, GH, Growth Factor Insulin-like (IGF-1), and cortisol in response to exercise. Exercise performance was also evaluated. Fifteen trained runners were divided into groups supplemented with 6 g of L-arginine (ARG) or placebo (PLA). Blood samples were collected before supplementation (T0), immediately after the first exercise session (T1), after the second exercise session (T2), and after 20 min of rest (T3). The exercise consisted of two bouts of 5 km time-trial running test. There was a significant increase in serum GH (T0: 3.28±0.95 vs. 3.21±0.5 ng/mL; T1: 4.35±0.23 vs. 4.17±0.13 ng/mL; T2: 4.22±0.25 vs. 4.17±0.09 ng/mL; T3: 4.14±0.29 vs. 4.13±0.18 ng/mL) and cortisol (T0: 198.71±53.77 vs. 207.57±69.51 nmol/L; T1: 458.16±116.12 vs. 433.26±101.77 nmol/L; T2: 454.61±125.21 vs. 431.88±74.82 nmol/L; T3: 311.14±102.91 vs. 362.26±110.42 nmol/L) after T1, T2, and T3, with no significant difference between the ARG and PLA groups, respectively. There was also no significant difference observed in the variables of IGF-1, insulin, and total running time between the ARG and PLA groups. The supplementation of L-arginine did not appear to stimulate the production of insulin, GH, and IGF-1 and, thus, provided no benefit in hormonal response or exercise performance in trained runners.
... While L-Arg has been shown to increase growth hormone-releasing hormone, it does suppress endogenous growth hormone-inhibiting hormone and increases insulinlike growth factor 1 [80,81]. However, oral administration of L-Arg does not augment exercise-induced growth hormone increase [82]. Furthermore, growth hormone response to specific amino acid consumption is reportedly reduced in well-trained athletes [83]. ...
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Consumption of amino acids L-arginine (L-Arg) and L-citrulline (L-Cit) are purported to increase nitric oxide (NO) production and improve physical performance. Clinical trials have shown relatively more favorable outcomes than not after supplementing with L-Cit and combined L-Arg and L-Cit. However, in most studies, other active ingredients such as malate were included in the supplement. Therefore, the aim of this study was to determine the efficacy of consuming standalone L-Arg, L-Cit, and their combination (in the form of powder or beverage) on blood NO level and physical performance markers. A systematic review was undertaken following PRISMA 2020 guidelines (PROSPERO: CRD42021287530). Four electronic databases (PubMed, Ebscohost, Science Direct, and Google scholar) were used. An acute dose of 0.075 g/kg of L-Arg or 6 g L-Arg had no significant increase in NO biomarkers and physical performance markers (p > 0.05). Consumption of 2.4 to 6 g/day of L-Cit over 7 to 16 days significantly increased NO level and physical performance markers (p < 0.05). Combined L-Arg and L-Cit supplementation significantly increased circulating NO, improved performance, and reduced feelings of exertion (p < 0.05). Standalone L-Cit and combined L-Arg with L-Cit consumed over several days effectively increases circulating NO and improves physical performance and feelings of exertion in recreationally active and well-trained athletes.
... This likely stems from the standard clinical test for growth hormone insufficiency which is based on a hormone challenge test using arginine infusion. The levels of amino acids that must be ingested to provoke a measureable increase in growth hormone secretion are generally not well tolerated and, in any case, may not be greater than the spikes in growth hormone and IGF-1 that can be produced with an intense bout of resistance exercise (Bucci et al. 1990;Kraemer et al. 1991;Chromiak and Antonio 2002). ...
... Podczas badań dotyczących podaży argininy w diecie i pod postacią suplementów uzyskano z kolei niejednoznaczne wyniki jej wpływu na poziom hormonu wzrostu (Campbell i in. 2004, Chromiak, Antonio 2002, Walberg-Rankin 1994. Fakt pulsacyjnego wydzielania GH, głównie w nocy, wydaje się sugerować, że podaż argininy przed snem może zwiększyć sekrecję tego hormonu (Jóźków, Mędraś 2009). ...
... Interestingly, in this study, fetal arginine, histidine, lysine, and ornithine were lower in fetal oIGF-1 compared to SAL. Arginine, lysine, and ornithine are known to stimulate growth hormone secretion; some studies have shown that histidine also has this effect (Chromiak and Antonio, 2002). Postnatally, growth hormone is a critical stimulator of IGF-1 secretion. ...
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IGF-1 is a critical fetal growth-promoting hormone. Experimental infusion of an IGF-1 analog, human recombinant LR3 IGF-1, into late gestation fetal sheep increased fetal organ growth and skeletal muscle myoblast proliferation. However, LR3 IGF-1 has a low affinity for IGF binding proteins (IGFBP), thus reducing physiologic regulation of IGF-1 bioavailability. The peptide sequences for LR3 IGF-1 and sheep IGF-1 also differ. To overcome these limitations with LR3 IGF-1, we developed an ovine (sheep) specific recombinant IGF-1 (oIGF-1) and tested its effect on growth in fetal sheep. First, we measured in vitro myoblast proliferation in response to oIGF-1. Second, we examined anabolic signaling pathways from serial skeletal muscle biopsies in fetal sheep that received oIGF-1 or saline infusion for 2 hours. Finally, we measured the effect of fetal oIGF-1 infusion versus saline infusion (SAL) for 1 week on fetal body and organ growth, in vivo myoblast proliferation, skeletal muscle fractional protein synthetic rate, IGFBP expression in skeletal muscle and liver, and IGF-1 signaling pathways in skeletal muscle. Using this approach, we showed that oIGF-1 stimulated myoblast proliferation in vitro . When infused for 1 week, oIGF-1 increased organ growth of the heart, kidney, spleen, and adrenal glands and stimulated skeletal myoblast proliferation compared to SAL without increasing muscle fractional synthetic rate or hindlimb muscle mass. Hepatic and muscular gene expression of IGFBPs one to three was similar between oIGF-1 and SAL. We conclude that oIGF-1 promotes tissue and organ-specific growth in the normal sheep fetus.
... Besides its alleged effect on vasodilation, L-arginine has also been mentioned as a possible stimulus of growth hormone (GH) release [4][5][6][7][8]. This condition may increase rates of protein synthesis and, consequently, accelerate muscle recovery in physically active individuals. ...
Article
It has been hypothesized that l-arginine improves exercise performance by increasing nitric oxide synthesis and levels of insulin and growth hormone (GH). Metabolic and hormonal responses to chronic l-arginine supplementation may clarify the mechanisms underlying its putative physiologic effects on physical performance. Therefore, the aim of this study was to investigate the effects that 4 weeks of supplementation with l-arginine would have on metabolic and hormonal parameters at rest and in response to exercise. Fifteen healthy runners were divided into treatment (ARG; 6 g l-arginine) and placebo (PLA; 6 g cornstarch) groups. On the first visit, blood samples were collected for baseline, and the supplement or placebo was provided. After 4 weeks of supplementation (second visit), blood samples were collected at the following intervals: at rest, immediately after the first 5-km time-trial running test (5km-TT), immediately after the second 5km-TT, and after 20 minutes of recovery (+20). In addition to exercise performance (total running time), plasma nitrate, nitrite, nitrate plus nitrite, cyclic guanosine monophosphate, lactate, ammonia and serum insulin, GH, insulin-like growth factor 1, and cortisol concentrations were evaluated. There were significant increases in plasma nitrite, cyclic guanosine monophosphate, lactate, ammonia and serum GH, and cortisol at the first 5km-TT, immediately after the second 5km-TT, and +20 in both ARG and PLA. Nitrate plus nitrite and nitrate increased only at +20. No significant change was observed in serum insulin and insulin-like growth factor 1 in any sample period. Total running time did not differ significantly between the 2 tests, in either ARG or PLA. Thus, according to our results, 4 weeks of l-arginine supplementation did not cause beneficial changes in metabolic and hormonal parameters, beyond those achieved with exercise alone.
... Both aerobic training and arginine supplementation were separately able to normalise serum insulin, but the combined treatment did not exert synergistic effects. Arginine is an amino acid involved in a number of physiological processes, and it is considered one of the most powerful secretagogues of the growth hormone (70) . It has also been described as a powerful stimulator of insulin secretion that acts directly on pancreatic β-cells (71) . ...
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Endothelial function is a key mechanism in the development of CVD. Arginine and exercise are important non-pharmacological strategies for mitigating the impact of metabolic changes in the metabolic syndrome, but the effect of their combined administration is unknown. Thus, the aim of this study was to investigate the isolated and combined effects of aerobic training and arginine supplementation on metabolic variables and vascular reactivity in rats at high risk for developing the metabolic syndrome. Wistar rats were divided into two groups: control and fructose (F – water with 10 % fructose). After 2 weeks, the F group was divided into four groups: F, fructose+arginine (FA, 880 mg/kg per d of l -arginine), fructose+training (FT) and fructose+arginine+training (FTA); treatments lasted for 8 weeks, and no difference was observed in body mass gain. Arginine did not improve the body protein content, and both the FA and FT groups show a reversal of the increase in adipose tissue. Insulin increase was prevented by training and arginine, without additive effect, and the increase in serum TAG was prevented only by training. The F group showed impaired endothelium-dependent vasodilation and hyperreactivity to phenylephrine, but arginine and training were capable of preventing these effects, even separately. Higher nitric oxide level was observed in the FA and FT groups, and no potentiating effect was detected. Thus, only training was able to prevent the increase in TAG and improve the protein mass, and training and arginine exert similar effects on fat content, insulin and endothelial function, but these effects are not additive.
... Lys modulates the production and activities of hormones such as insulin, insulin-like growth factor 1 (IGF-1) [52], and growth hormone (GH) [53]. Oral administration of Lys and Arg (1:1) enhanced both peak GH secretion and somatomedin-C bioactivity compared to the same dose of Arg alone in young adult men [54], but had no effect in old men [55]. ...
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l-Lysine (Lys) is a popular additive in foods, but the physiological effects of excess Lys supplementation are poorly understood and upper limits of safe intake have not been established. The objectives of this study were to examine the effects of dietary supplementation with increasing amounts of Lys on body weight (BW), food intake, and various blood hematological and biochemical parameters in rats. Male Sprague–Dawley rats at 10 weeks of age were assigned to ten diet groups (eight rats/group) and fed diets containing either 7% or 20% casein and supplemented with either 0% (Control), 1.5%, 3%, 6% Lys, or 6% Lys + 3% arginine for 1 week. Rats fed 7% casein with ≥ 1.5% Lys supplementation had lower serum albumin and leptin and higher LDL cholesterol (LDLC), ratios of total cholesterol (TC):HDL cholesterol (HDLC) and LDLC:HDLC than those fed 7% casein Control diet (P < 0.05). Rats fed 7% casein diet supplemented with 3% Lys diet had lower BW gain, food intake, serum alkaline phosphatase activity, and increased mean corpuscular hemoglobin concentration, blood urea nitrogen and serum pancreatic polypeptide compared to rats fed the Control diet (P < 0.05). Addition of 6% Lys in 7% casein caused significant BW loss (P < 0.001) and altered additional parameters. Addition of 6% Lys in a 20% casein diet reduced BW gain and food intake and altered numerous parameters. Arg supplementation normalized many of the endpoints changed by Lys. Collectively, these results show that Lys supplementation affects BW, food intake and a number of hematological and biochemical parameters. These effects of Lys supplementation were confined primarily in diets with lower levels of dietary protein. In the context of a low protein diet (7% casein), levels of Lys supplementation ≥ 1.5% may exert adverse health effects in rats.
... Importantly, arginine is known to promote the overall body weight, carcass weight, lean deposition, and muscle development in poultry under normal and heat stress conditions (Fernandes et al., 2009;Castro et al., 2019;Kalvandi et al., 2022). Alongside this, it was reported that arginine can promote cell and tissue growth via its capacity to stimulate the release of key growth factors such as insulin, GH, and IGFs into the blood (Chromiak and Antonio, 2002;Oh et al., 2017). However, it is yet to be ascertained whether L-Citrulline can exert growthpromoting effects on poultry. ...
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Heat stress adversely affects the growth performance, muscle development, and protein metabolism in poultry. l-Citrulline (L-Cit), is a non-essential amino acid that is known to stimulate muscle protein synthesis under stress conditions. This study investigated whether L-Cit could influence the growth performance, amino acid profile, and protein metabolism in broilers exposed to high ambient temperature. In a 2 × 2 factorial arrangement, Arbor acre broilers (288 chickens) were fed with basal diet (CON) or 1% L-Cit supplemented diet and later subjected to either thermoneutral (TNZ: 24°C, 24 h/d) or heat stress (HS: 35°C for 8 h/d) environment for 21 days. The results showed that L-Cit diet promoted the body weight and body weight gain of broilers higher than the CON diet, and it further alleviated HS suppression of body weight and feed intake at certain periods (p < 0.05). Plasma urea, uric acid, glucose, and total cholesterol were elevated during HS, whereas, the triglyceride content was decreased (p < 0.05). Serum amino acids including citrulline, alanine, aspartate, and taurine were decreased by HS. L-Cit supplementation restored the citrulline level and alleviated HS induction of 3-methylhistidine (p < 0.05). L-Cit supplementation increased the plasma growth hormone (GH) and insulin-like growth factor-1 (IGF-1) concentration, as well as the GH concentration in the breast muscle (p < 0.05). The mRNA expression showed that HS elicited tissue-specific responses by upregulating some growth factors in the breast muscle, but downregulated the GH receptor, GH binding protein, and IGF-1 expression in the hypothalamus. L-Cit supplementation upregulated the GHRH and IGFBP2 expression in the hypothalamus. L-Cit also upregulated the expression of IGF-1R and IGFBP2 in the breast muscle of HS broilers. The total mTOR protein level in the breast muscle of HS broilers was also increased by L-Cit diet (p < 0.05). Therefore, this study demonstrated that HS negatively affected the growth performance of broilers and dysregulated the expression of growth factors related to protein metabolism. Contrarily, L-Cit promoted the growth responses of broilers via its stimulation of circulating GH/IGF-1 concentration. To certain extents, L-Cit supplementation elicited protective effects on the growth performance of HS broilers by diminishing protein catabolism.
... More specifically, some studies have shown that decreased consumption of branched chain amino acids, as well as methionine and tryptophan diets may be positively associated with longevity [87]. Interestingly, these results are congruent with the well-known ability of some amino acids (such as arginine, lysine and ornithine) to induce GH secretion [89]. Therefore, it is not surprising that PR diets are also associated with decreased insulin and IGF-1 levels, as well as decreased mTOR activity [90,91]. ...
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Progress made in the years of aging research have allowed the opportunity to explore potential interventions to slow aging and extend healthy lifespan. Studies performed in yeast, worms, flies and mice subjected to genetic and pharmacological interventions have given insight into the cellular and molecular mechanisms associated with longevity. Furthermore, it is now possible to effectively modulate pathways that slow aging at different stages of life (early life or at an adult age). Interestingly, interventions that extend longevity in adult mice have had sex-specific success, suggesting a potential link between particular pathways that modulate aging and sex. For example, reduction of the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis at an adult age extends lifespan preferentially in females. Moreover, several postnatal dietary interventions tested by the ‘Intervention Testing Program (ITP)’ from the National Institute of Aging (NIA) have shown that while pharmacological interventions like rapamycin affect the IGF-1/insulin pathway and preferentially extend lifespan in females; dietary compounds that target other cellular pathways are effective only in male mice—indicating mutually exclusive sex-specific pathways. Therefore, a combination of interventions that target non-overlapping aging-related pathways appears to be an effective approach to further extend healthy lifespan in both sexes. Here, we review the germline and postnatal mouse lines that target the GH/IGF-1 axis as a mechanism to extend longevity as well as the dietary compounds that tested positive in the NIA program to increase lifespan. We believe that the interventions reviewed in this paper could constitute feasible combinations for an extended healthy lifespan in both male and female mice.
... There are varieties of GH products abused by the athletes for ergogenic effects that include: 1. rhGH, which acts on GH receptors. 2. GH secretagogues, i.e., GH releasing hormone (GHRH) and its analogs; GH releasing peptides (also known as ghrelin analogs) which acts on ghrelin receptors to enhance GH release; and the amino acids, e.g., ornithine or arginine, to enhance the secretion of GH [2][3]. ...
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Septic arthritis of sternoclavicular joint (SCJ) is a rare disease, however, not uncommon in patients who abuse intravenous drugs. It can present with a wide range of manifestations that can pose diagnostic challenges, which can result in a delay in diagnosis and treatment. Over the last few decades, there is a surge in the use of nonprescription recombinant human growth hormone (rhGH) by the young healthy population and athletes for its purported ergogenic effects. Furthermore, we lack quantitative information about the adverse effects of the chronic use of rhGH in a healthy population due to the scarcity of epidemiological data. We are reporting a case of a young male athlete who was chronically using the subcutaneous rhGH formulation to build lean body mass, and presented with septic arthritis of right SCJ due to methicillin-sensitive Staphylococcus aureus (MSSA) complicated by a necrotic inflammatory response involving the mediastinum which infiltrated the apical lung parenchyma. The clinical presentation masqueraded as the mediastinal mass raising the suspicion of mediastinal malignancy. Histological analysis of the tissue of SCJ and mediastinal area revealed no malignant cells but a lymphocyte-predominant inflammatory response with germinal centers was observed, which was an atypical response to MSSA bacterial infection. We have reviewed the literature to elucidate the immune-modulatory effect of rhGH, as the chronic use of rhGH by our patient probably has contributed to an atypical immune response to MSSA. The patient was treated with an extended duration of parenteral antibiotics and multiple incision and debridements to achieve complete resolution of infection over the next six months. This is a unique case of septic arthritis of right SCJ in a patient on chronic subcutaneous rhGH which masqueraded as a mediastinal mass raising concern of malignancy; moreover, it highlights the probable immune-modulatory role of rhGH which instigated an atypical immune response to MSSA infection.
... Moreover, L-ORN has a main role in burning up excess fat in the body and is used for enhancing the workability of the immune system. [3][4][5][6][7] Several techniques were reported in the literature for the determination of L-ORN. These techniques are mainly chromatography based. ...
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A simple and highly sensitive univariate calibration strategy based on ultraviolet-visible (UV-Vis) absorption spectroscopy and assisted by multivariate screening and optimization was utilized for the determination of l-ornithine (l-ORN) as such and in the alimentary supplements. l-ORN, an OTC marketed amino acid, is widely used for bodybuilding and might be abused by athletes. A nucleophilic substitution reaction using 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) was the basis of the current investigation. Plackett-Burman design (PBD) and a response surface optimizer as screening and fine-tuning strategies, respectively, were instigated. Four numerical variables, reaction time (RT), temperature (Temp), pH and reagent volume (RV), and one categorical variable, the diluting solvent (DS), were considered. Absorbance of the yellow-colored adduct at 469 nm was the response studied. Pareto analysis, along with analysis of variance (ANOVA) were used to ascertain the significant variables (screening phase) and their domains (optimization phase). Response transformation and stepwise analysis were employed when necessary. Probability, cube and individual value plots were used to get an insight into the statistical impact of the variables tested. Multiple responses' optimization was performed using Derringer's function. Calibration curves were linear in the range of 5-50 μg mL-1. Job's technique of continuous variation showed that the stoichiometric ratio is 2 : 1 (NBD-Cl : l-ORN). The proposed technique was successfully applied to the dietary supplements of l-ORN, inferring no interference from adjuvants and excipients. Analytical performance of this technique was validated conforming to the ICH standards.
... In addition to GABA, various amino acids (e.g. arginine, lysine, and branched-chain amino acids) can promote GH secretion [35,36]. Therefore, gradually increasing GH concentrations in the WP group may be related to amino acids included in whey powder. ...
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Background Oral gamma-aminobutyric acid (GABA) supplementation increases growth hormone (GH) serum levels and protein synthesis. Therefore, post-exercise supplementation using GABA and protein may help enhance training-induced muscle hypertrophy. We evaluated whether GABA with whey protein enhanced muscular hypertrophy in men after progressive resistance training. Methods Twenty-one healthy men (26 - 48 years) were randomized to receive whey protein (WP; 10 g) or whey protein + GABA (WP + GABA; 10 g + 100 mg) daily for 12 weeks. Both groups performed resistance training twice per week (three sets of 12 repetitions at 60% of maximal strength; leg press, leg extension, leg curl, chest press, and pull down). Body composition was assessed using dual-energy X-ray absorptiometry. Results In the WP + GABA group, resting plasma GH concentrations were significantly elevated at 4 and 8 weeks, compared to baseline. However, resting plasma GH concentrations in the WP group were only significantly elevated at 8 weeks. After 12 weeks, the WP + GABA group exhibited significantly greater increase in whole body fat-free mass than the WP group. Conclusions The GABA and whey protein combination was more effective for increasing whole body fat-free mass; daily GABA supplementation may help enhance exercise-induced muscle hypertrophy.
... Ergogenic response of arginine has also been reported by Chromiak and Antonio (2002). The role of arginine supplementation on healthy and diseased populations has to be concluded (Campbell, 2004). ...
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Arginine is metabolically flexible amino acid with major role in protein synthesis and detoxification of ammonia. It is involved in several metabolic pathways for the production of biologically active compounds such as creatine, nitric oxide, ornithine, glutamate, agmatine, citrulline and polyamines. Regarding this all, we review the crucial role of arginine in metabolism, diversified prospective uses and pharmacological applications. Arginine plays an important role in the treatment of tumorigenesis, asthama, gastric, erectile dysfunction, apoptosis, melanoma and congestive heart failure. Ability to produce nitric oxide offers various applications as in the prevention of age and hair loss. It serves as a precursor of creatine with ergogenic potential. The ability to increase endogenous growth hormone makes arginine a preferred supplement for the improvement of physical performance. In the present study details about the pharmacological applications of arginine based on modern scientific investigations have been discussed. There are immense properties hidden in arginine that need to be explored using the scientific investigations to make it beneficial for the medicine and human health. More research is needed to evaluate the role of arginine supplementation on exercise performance and training adaptations in healthy and diseased populations before taking any conclusions.
... Although intravenous perfusion with this amino acid stimulates GH secretion at rest [251] and during exercise [252], the effects of its oral use remain unclear [253]. Thus, whereas some authors have reported increased GH after a single dose (7 g) of arginine in young men [254], others have found no differences in comparison with the ingestion of a placebo [255][256][257]. ...
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Purpose Several supplements are purported to promote muscle hypertrophy and strength gains in healthy subjects, or to prevent muscle wasting in atrophying situations (e.g., ageing or disuse periods). However, their effectiveness remains unclear. Methods This review summarizes the available evidence on the beneficial impacts of several popular supplements on muscle mass or strength. Results Among the supplements tested, nitrate and caffeine returned sufficient evidence supporting their acute beneficial effects on muscle strength, whereas the long-term consumption of creatine, protein and polyunsaturated fatty acids seems to consistently increase or preserve muscle mass and strength (evidence level A). On the other hand, mixed or unclear evidence was found for several popular supplements including branched-chain amino acids, adenosine triphosphate, citrulline, β-Hydroxy-β-methylbutyrate, minerals, most vitamins, phosphatidic acid or arginine (evidence level B), weak or scarce evidence was found for conjugated linoleic acid, glutamine, resveratrol, tribulus terrestris or ursolic acid (evidence level C), and no evidence was found for other supplements such as ornithine or α-ketoglutarate (evidence D). Of note, although most supplements appear to be safe when consumed at typical doses, some adverse events have been reported for some of them (e.g., caffeine, vitamins, α-ketoglutarate, tribulus terrestris, arginine) after large intakes, and there is insufficient evidence to determine the safety of many frequently used supplements (e.g., ornithine, conjugated linoleic acid, ursolic acid). Conclusion In summary, despite their popularity, there is little evidence supporting the use of most supplements, and some of them have been even proven ineffective or potentially associated with adverse effects.
... These characteristics are reported to occur in skeletal muscle cells stimulated by EPS. Among the ergogenic aids, the essential amino acid L-arginine enhances athletic performance by increasing the synthesis of creatine and nitric oxide (NO), which rapidly promotemaximum muscular strength [13][14][15] . NO is synthesized under the control of NO synthase (NOS) 16 . ...
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Purpose: This study aimed to examine the independent effect of electrical pulse stimulation(EPS) and nitric oxide(NO) on muscle contraction and their synergistic or combined effect on contraction phenomenon using C2C12 mouse skeletal muscle cells. Methods: Some differentiated C2C12 myotube cells were untreated (control). Other cells did not receive EPS and did receive 0.5, 1.0, or 2.0 mM of the NO donor, S-nitroso-N-acetyl-penicillamine (SNAP; -E/S0.5, -E/S1.0, and -E/S2.0, respectively). For the EPS treatments (0.3 V/mm, 1.0 Hz, and 4.0 ms), differentiated C2C12 myotube cells received only EPS or both EPS and the SNAPtreatments at the same concentrations (+E/-S, +E/S0.5, +E/S1.0, and +E/S2.0, respectively). All samples were then cultured for 4 days. Results: Differentiated C2C12 cellswere stimulated by the EPS, NO, and EPS+NO treatments. The cell length of the +E/S2.0 Group after the 4-day culture (84.2±13.2㎛) was the shortest of all the groups. The expressions of AMPK, JNK, Akt, eNOS, GLUT4, and PGC1α proteins were noticeably dominant. The results indicated synergistic effect on muscle contraction of simultaneously applied EPS and SNAP. Conclusion: Motor skills were significantly improved when exercise was accompanied by the intake of NO precursor and/or NO, compared to that upon their independent application or treatment.
... Lysine, as one of the essential amino acids, is, in fact, one of the most important amino acids used to stimulate the growth hormone, and since the transglutaminase strengthens the binding of this amino acid and glutamine in the body, can be resulted that TG may indirectly effect on growth hormones [34]. Furthermore, transglutaminase allows for the development of entirely new products, like as protein films used to coat fresh vegetables and fruits and processed food products to extend their shelf life [6 ,35]. ...
Article
Nowadays, food manufacturers try to develop new products with unique functional characteristics; however, these products have not always been to the benefit of the consumer and in some cases have led to consumer's health problems. The use of transglutaminase (TG) in the food industry is very common. Transglutaminase catalyzes covalent bond between lysine and glutamine in peptides and protein to achieve a more stable, rigid and complex product. From the health point of view, TG can reduce allergy, control energy intake from foods and act as mediator in wound healing. Besides all these benefits, evidences have suggested that transglutaminase (mTG) action in food products might cause autoantigen in celiac disease (CD) population. Microbial transglutaminase cross-linked gluten may be hazardous for CD since the enzymes can deamidate gluten and thus, mimic endogenous tissue transglutaminase (tTG). On the other hand, numerous studies indicated that transglutaminase is responsible for some neurodegenerative diseases such as Alzheimer disease and Huntington disease (HD). In the present article, recent achievements on health aspects of transglutaminase in food products are reviewed.
... Although there is clinical evidence that pharmaceutical grade GHRP's and some non-peptide secretagogues can increase GH and IGF-1 levels at rest and in response to exercise, it has not been demonstrated that such increases lead to an increase in skeletal muscle mass [343]. Finally, Chromiak and Antonio [344] reported that oral ingestion of many secretagogues fail to consistently stimulate hormone increases in growth hormone and fail to stimulate greater changes in muscle mass or strength. Currently, there is no convincing scientific evidence that secretagogues support increases in lean body mass or muscular performance. ...
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Background: Sports nutrition is a constantly evolving field with hundreds of research papers published annually. In the year 2017 alone, 2082 articles were published under the key words 'sport nutrition'. Consequently, staying current with the relevant literature is often difficult. Methods: This paper is an ongoing update of the sports nutrition review article originally published as the lead paper to launch the Journal of the International Society of Sports Nutrition in 2004 and updated in 2010. It presents a well-referenced overview of the current state of the science related to optimization of training and performance enhancement through exercise training and nutrition. Notably, due to the accelerated pace and size at which the literature base in this research area grows, the topics discussed will focus on muscle hypertrophy and performance enhancement. As such, this paper provides an overview of: 1.) How ergogenic aids and dietary supplements are defined in terms of governmental regulation and oversight; 2.) How dietary supplements are legally regulated in the United States; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General nutritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of nutritional approaches to augment skeletal muscle hypertrophy and the potential ergogenic value of various dietary and supplemental approaches. Conclusions: This updated review is to provide ISSN members and individuals interested in sports nutrition with information that can be implemented in educational, research or practical settings and serve as a foundational basis for determining the efficacy and safety of many common sport nutrition products and their ingredients.
... Alguns autores têm sugerido que a ingestão de proteínas em torno de 15% do VET é o suficiente para atender às necessidades de desportistas e atletas e que há poucas evidências científicas que justifiquem um consumo superior visan- do aumentar a massa muscular. [34][35][36] 40,41 Além disso, como a proteína é a principal fonte de produção ácida endógena através da excreção de sulfato, essa produção aumentada pode influenciar negativamente a densidade mineral óssea, se não for balanceada com uma dieta adequada (frutas e vegetais). 42 Outra substância bastante utilizada pelos usuários de academia foi a creatina, cujo maior percentual encontrado foi de 89%. ...
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O objetivo da presente revisão sistemática foi traçar a prevalência, as formas de indicação e os efeitos adversos dos suplementos alimentares (SA) e esteroides anabólicos androgênicos (EAA), cujo uso é relatado por praticantes de musculação nas academias de ginástica do Brasil. Para desenvolvimento deste estudo foi realizada, em novembro de 2011, uma busca nas bases de dados Medline, Scielo, Bireme e Lilacs utilizando as palavras-chave: esteroides anabólicos androgênicos, suplementos nutricionais e academias de ginástica. Para ser incluído, o estudo deveria ter investigado o uso de recursos ergogênicos em academias do Brasil. De acordo com os critérios de inclusão, foram selecionadas em um primeiro momento 93 investigações, mas apenas 18 foram incluídas. Os estudos selecionados demonstraram que as regiões Sul e Sudeste são as que possuem maior número de estudos. A maior prevalência de consumo dos SA foi em Belo Horizonte (90,8%), seguido por Vitória (70%), Cascavel (66%) e Curitiba (50,61%), e os produtos mais consumidos foram: proteínas, aminoácidos e creatinas. Para os EAA, a maior prevalência encontrada foi em Belo Horizonte com 85%, seguido por Aracaju (31%) e Rio Grande do Sul (24,9%). Os produtos mais utilizados foram o Decanoato de Nandrolona, a Testosterona e o Estanozolol. Os efeitos colaterais predominantes dos EAA foram surgimento de acne (46 a 94%) e agressividade (47 a 73%). Tanto o consumo de SA quanto o uso dos esteroides anabólicos androgênicos encontram-se exacerbados nas academias brasileiras, principalmente, na região Sudeste. Além disso, o uso abusivo dos EAA ocorre devido à falta de informações sobre suas contra indicações, repercutindo em inúmeros efeitos adversos à saúde.
The nutritional significance of essential amino acids, as well as non-essential amino acids, is well documented in poultry production with regards to growth performance and protein accretion. However, the function of amino acids in the stress response is still unclear. L-Pipecolic acid, a L-lysine metabolite in the brain, induced a hypnotic and sedative effect acting via the - aminobutyric acid receptors. L-Arginine also induced a sedative effect via its metabolism to L-ornithine. In addition, three-carbon nonessential amino acids like L-alanine, L-serine and L-cysteine also induced sedative effects. These facts suggest that the requirement for amino acids in both essential and non-essential types may require reconsideration to add the concept of stress amelioration in the future.
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l-lysine being one of the essential amino acids is not produced by the body, but is obtained through diet. l-lysine determination is important in the food and pharmaceutical industries as well as have medical and diagnostic applications. The normal l-lysine levels in a healthy human serum sample is 150 to 250 μmol/L. There is imbalance in l-lysine levels in certain diseased conditions. So, it could be a biomarker for diagnosis. Various basic methods are available for the determination of l-lysine such as colorimetric, radioisotope dilution, chromatographic, fluorometric and voltammetric methods. These methods have certain disadvantages like sample pretreatment, costly, time consuming and requirement of skilled personnel. These drawbacks are overcome by the use of biosensors due to their high sensitivity, stability and specificity. The present review article discusses about the principles, merits and demerits of the various analytic methods for determination of l-lysine with special emphasis on biosensors. l-lysine biosensors work ideally under the optimum pH 5 to 10, potential range -0.05 to 1.5 V, temperature 25 to 40 °C, with linear range 0.01 to 5500 μM, detection limit 0.000004 to 650 μM and response time 2 to 300 s. The sensor had storage stability between 14 and 200 days.
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We found that intraduodenal administration of L-ornithine (L-Orn) stimulates growth hormone (GH) secretion in Wistar rats, and then investigated its mechanism. GH-releasing activity after intraduodenal administration of L-Orn was blocked by [D-Lys³]-GHRP-6, an antagonist of the ghrelin receptor; however, L-Orn (100 μM) had no affinity for the ghrelin receptor, suggesting that the GH-releasing activity of L-Orn is mediated via ghrelin release and activation of ghrelin receptor. Intraduodenally administered L-Orn increased ghrelin mRNA expression in the duodenum but not in the stomach or hypothalamus. In addition, L-Orn-induced GH-releasing activity was inhibited by propranolol, an antagonist of β-adrenergic receptor, which is known to be coupled to ghrelin release. In conclusion, intraduodenally administered L-Orn stimulates GH secretion through the sympathetic nervous and ghrelin systems.
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The purpose of this study was to investigate the effect of exercise and/or L-arginine on abdominal fat, IGF-1 on GH/IGF-1 axis, fibrinogen, and PAI-1 in aged and obese rats. Male Sprague-Dawley rats were treated with a D-galactose aging inducing agent (50 mg/kg) given intraperitoneally for 12 weeks. Thirty-two male Sprague-Dawley rats were treated and divided into four groups: aging-high fat diet group (AG+HF), AG+HF with L-arginine intake group (AG+LA), AG+HF with exercise group (AG+EX), and AG+EX with L-arginine intake group (AG+LA+EX). The experimental rats underwent treadmill training (60 min/day, 6 days/week at 0% gradient) for 12 weeks. L-arginine was given orally (150 mg/kg/day) for 12 weeks. After the experiment, blood was collected from the left ventricle and abdominal fat was extracted. The results showed that GH was significantly increased in AG+EX and AG+AL+EX. IGF-1 was significantly increased in both the AG+AL+EX and AG+EX group (
The effects of intra-duodenal infusion of methionine (Met), lysine (Lys) and leucine (Leu) on dry matter intake (DMI), the concentrations of insulin-like growth factor I (IGF-I), growth hormone (GH) and insulin in plasma, and liver IGF-I mRNA level were investigated in two experiments for Liuyang Black growing wether goats. In Experiment 1, three goats (10.0??.1 kg) were fitted with ruminal, proximal duodenal and terminal ileal fistulaes to determine the infusion amounts of Met, Lys and Leu at the duodenum according to essential amino acid flows into the duodenum and their apparent digestibility. The infusion amounts were 0.77 g/d, 0.91 g/d and 0.58 g/d respectively. In Experiment 2, 4 groups of goats (10.0??.2 kg) for each group, were cannulated at the duodenum, and were infused with a mixture of Met, Lys and Leu (Control), or mixtures with 21% Met, Lys or Leu replaced with glutamate respectively on a nitrogenous basis. The replacement of 21% Met, Lys or Leu with glutamate did not affect intakes of maize stover, concentrate or both (p>0.05) when compared with the control. The replacement of 21% Met or Lys significantly (p
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One of the most common-sought after goals in athletic performance is attaining and maintaining muscle mass. From protein to creatine, arginine to human growth hormone, how is one to determine what really works, what is legitimate, and what is merely another gimmick in the supplement industry? Coupling the array of supplements with the unique performance needs of an athlete creates an infinite amount of possible combinations. How do you know what is the right combination for successfully building the desired amount of muscle mass, maintaining an “optimal” body composition, and (during periods when additional body mass is desired) ensuring lean mass is gained over fat mass? It is with great time, research, and a foundation laid for us by our predecessors in the field of sports nutrition that we write this chapter on muscle building and optimizing lean body mass. By the end of this chapter you should be able to: Describe the muscle building process Define and determine net protein balance Describe how genetics play a role in muscle growth Know the recommended amounts of protein for gaining muscle Know the suggested protein: carbohydrate ratio for optimal muscle hypertrophy Define nutrient timing and its role in muscle hypertrophy Explain the difference between whey, casein, egg, soy, and vegan protein supplements Explain why and when supplementing with BCAAs are important to muscle growth Explain the major hormones that play a role in muscle growth Explain the potential benefits and drawbacks of anabolic steroids Define the role of IGF in muscle growth Describe the creatine-phosphate system and why creatine is used for muscle hypertrophy Explain why supplements that promote the production of nitric oxide are used by athletes Explain how resistance training stimulates muscle hypertrophy
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Background: Lysinuric protein intolerance (LPI; MIM# 222700) is a rare metabolic disorder caused by a defective cationic amino acids (CAA) membrane transport leading to decreased circulating plasma CAA levels and resulting in dysfunction of the urea cycle. Short stature is commonly observed in children with LPI and has been associated with protein malnutrition. A correlation between LPI and growth hormone deficiency (GHD) has also been postulated because of the known interaction between the AA arginine, ornithine, and lysine and growth hormone (GH) secretion. Our report describes a case of GHD in an LPI patient, who has not presented a significant increase in growth velocity with recombinant-human GH (rhGH) therapy, suggesting some possible pathogenic mechanisms of growth failure. Case presentation: The proband was a 6-year-old boy, diagnosed as suffering from LPI, erythrophagocytosis (HP) in bone marrow, and short stature. Two GH provocative tests revealed GHD. The patient started rhGH therapy and a controlled-protein diet initially with supplementation of oral arginine and then of citrulline. At 3-year follow-up, no significant increase in growth velocity and in insulin-like growth factor-1 (IGF-1) levels was observed. Inadequate nutrition and low plasmatic levels of arginine, ornithine, lysine, and HP may have contributed to his poor growth. Conclusion: Our case suggests that growth failure in patients with GHD and LPI treated with rhGH could have a complex and multifactorial pathogenesis. Persistently low plasmatic levels of lysine, arginine, and ornithine, associated with dietary protein and caloric restriction and systemic inflammation, could determine a defect in coupling GH to IGF-1 production explaining why GH replacement therapy is not able to significantly improve growth impairment. We hypothesize that a better understanding of growth failure pathophysiology in these patients could lead to the development of more rational strategies to treat short stature in patients with LPI.
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GH is banned by the World Anti-Doping Agency as a performance-enhancing anabolic agent. Doping with GH likely began in the early 1980s and became more prevalent with the advent of recombinant technology well before any scientific evidence of benefit. The expectation that GH improves physical function stems from its anabolic and lipolytic properties. Athletic performance depends on muscle strength and the energy required to power muscle function. In recreational athletes, GH selectively improves anaerobic sprint capacity but has not been proven to significantly enhance muscle strength, power, or maximum rate of oxygen consumption. GH is secreted as a family of isoform peptides in a pulsatile manner reflecting intermittent secretion and rapid clearance. Its anabolic actions are largely mediated by IGF-I, which stimulates whole-body protein synthesis, including skeletal muscle and collagen proteins. Two methods have been validated for detecting GH abuse in athletes. The first (the isoform method) is based on distinguishing pure recombinant 22-kDa GH from the heterogeneous isoforms secreted from the pituitary. The second (the marker method) is based on measuring blood levels of GH-responsive proteins, specifically IGF-I and the N-terminal propeptide of type III collagen (P-III-NP). Only a handful of athletes have been caught since the implementation of GH doping tests in 2004. The low rate likely reflects the limitation of in-competition testing using current methods. Improved detection rates may be achieved by more out-of-competition testing, introducing athletes' biological passports, and the development of novel methods. Governance, operational, technical, and political factors influence the effectiveness of an anti-doping program.
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Athletic endeavors push the limits of human performance and athletes often seek ergogenic aids to gain an edge. A nutritional ergogenic aid is defined as any nutrient capable of enhancing energy utilization, including energy production, control, and efficiency (Silver, J Am Acad Orthop Surg 9:61–70, 2001). A nutritional ergogenic aid sought commonly by athletes is protein (or amino acid) supplementation (Alvares et al., Appl Physiol Nutr Metab 37:115–126, 2012; Campbell et al., J Int Soc Sports Nutr 1:35–38, 2004; Chromiak and Antonio, Nutrition 18:657–661, 2002; Paddon-Jones et al., J Nutr 134:2888S–2894S, 2004; Shao and Hathcock, Regul Toxicol Pharmacol 50:376–399, 2008). l-arginine is an amino acid that has been purported to be ergogenic and, as such, has become very popular in the food supplement industry (Alvares et al., Appl Physiol Nutr Metab 37:115–126, 2012; Campbell et al., J Int Soc Sports Nutr 1:35–38, 2004; Paddon-Jones et al., J Nutr 134:2888S–2894S, 2004; Shao and Hathcock, Regul Toxicol Pharmacol 50:376–399, 2008; McConell, Curr Opin Clin Nutr Metab Care 10:46–51, 2007; Kanaley, Curr Opin Clin Nutr Metab Care 11:50–54, 2008). Recently, Maughan et al. (J Sports Sci 29:S57–66, 2011) noted l-arginine as an emerging and growing trend among athletes.
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A study entitled “Assessment of nutritional status of male and female wrestlers of district level ” was undertaken during 2010-2012. The purpose of the present investigation was to assess the nutritional status of male and female wrestlers of district level . A total of 150 male wrestlers and 150 female wrestlers were selected purposefully for study from various area of Punjab. General information such as age, education and occupation were collected through personal interview method by structured questionnaire. Information on sports activity, daily routine, food habits like type of diet, pattern of water consumption, number of meals or beverages consumed per day and special foods, foods taken and avoided for sports and frequency of consumption of different types of foods were collected. The demographic profile, dietary habits, exercise habits, sports activity were recorded by using a structured questionnaire. The salient findings of the study are summarized below. All the male wrestlers belonged to different age groups, more than half of wrestlers (87%) were in between 20-25 years of age group and only (13%) were in 25-30 years and in female wrestlers also more than half of co (60%) were in between 20-25 years of age and only (40%) were in 25-30 years. Regarding literacy level, high number of male wrestlers (66%) was graduates whereas, (27%) were post-graduates and (7%) were college students and in female wrestlers (48%) were graduates, (44%) are pursuing their post graduation and (8%) are pursuing their senior secondary and none of them were illiterates. Most of the players were in the field of sports since 2-4 years, majority of the players had been playing their game for 2-4 years, and had played at national level followed by state, district and university levels. Most of the players were practicing their game daily. Regarding practicing of exercises, all the players were practicing jumping, stepping and sprints daily. On an average almost all of them were doing warm-up exercise since 2-3 years. Majority of them were spending 5-10 minutes for jumping exercises followed by 15-30 minutes for stepping and 30-60 minutes for jogging. Most of the exercises were practiced during the morning hours. All the players were vegetarians, and were consuming 3 meals per day. Most of them were consuming 1-2 cups of morning beverage, more than half of the subjects were consuming 1-2 glasses of milk per day. Most of them were consuming milk products as special food followed by milk in the morning; almond and milk both in the morning and evening. Around 50 per cent of the respondents were consuming milk at night. Before the event, most of the players was in the habit of consuming fruit juice where as, majority of them were consuming glucose during the event and majority ofthem were consuming fruit juice after the event. Before the event majority of the wrestlers avoided heavy meals where as, most of the wrestlers avoided heavy meals during the event and heavy meals were avoided after the event. It was observed that majority of them consumed about 100-150 ml of water before event and most of them consumed 150-200 ml of water during the event, and majority of them consumed 1000 ml of water after the event. All the male wrestlers have higher mean value of height, waist circumference and waist to hip ratio as compare to female wrestlers. All the male wrestlers have higher mean values of nutrient intake as compare to female wrestlers. All the players were consuming cereals, pulses and milk, sugar and cooking oil daily, most of them were consuming cheese, green leafy vegetables, fruits, ghee, chocolates, sweets and soft drinks weekly twice. Most of them were consuming oil seeds, ghee, fruits, bakery products, noodles, street foods and ice cream once a week. Jaggery, bakery products, street foods were the foods consumed by most of the subjects every forth nightly; noodles and chats were consumed once a month and occasionally by most of the players. Burger, butter, ghee, cheese were consumed occasionally by the players. Most of the athletes never consumed eggs, chicken, fish, mutton and jiggery.
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The chick has a practical advantage in the screening process in that chicks require only small quantities of drugs. The chick separation stress paradigm has traditionally been recognized as a valid form of anxiolytic screening. Further, chick behavior involving standing motionless with eyes closed or sitting motionless with head drooped is nearly always associated with electrophysiological sleep. When centrally administered, some DNA-encoded L-α-amino acids, as well as some DNA-non-encoded amino acids, such as metabolites of L-α-amino acids, D-amino acid and β-amino acid, have shown sedative and/or hypnotic effects in chicks. The effects of some of these amino acids have subsequently been confirmed in humans. In conclusion, the chick model is convenient and useful for screening central functions of amino acids and their metabolites for hypnosis and sedation. Copyright © 2015. Published by Elsevier B.V.
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Dietary restriction (DR) refers to a reduction in food intake to induce undernutrition but not malnutrition, which extends the lifespan of multiple species. Although there are invertebrate aging models, such as the Caenorhabditis elegans and Drosophila melanogaster, aging studies in Lepidoptera are few in number and the underlying life-extending molecular mechanisms are not clear. Research on a broader range of animals is necessary to support generalizations on mechanisms of aging and rates of aging. The aim of this study was to further investigate genes and pathways associated with DR in Bombyx mori. Here, we used mRNA deep sequencing (RNA-seq) to further investigate genes and pathways associated with DR. The transcriptome profiles showed that most of the differentially expressed genes were upregulated following DR, and genes involved in amino acid and protein metabolism, RNA metabolism and translation, energy metabolism, nitrogen metabolism, and juvenile hormone pathway-related proteins were particularly affected. DR also affects the metabolism of uric acid and urea, which accumulated in silkworm following DR. We speculate that this may not be due to activation of uric acid biosynthesis, but rather by downregulating the degradation of uric acid and urea. These results may help us to understand the mechanisms by which DR prolong lifespan in insects and other animals.
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It was the aim of the present experiment to detect possible effects of branched-chain amino acids (BCAA) on the endocrine response to 1 h of continuous running. Blood samples were collected from 14 long-distance runners (age 24-42 years) in two different trials performed at 1-week intervals. In both trials (E and P) blood samples were collected at the following times: 9 a.m. (basal values sample), 10.30 a.m. (sample 90), 11.30 a.m. (sample 150), 12.30 p.m. (sample 210); the athletes performed 1 h of running at a constant predetermined speed between samples 90 and 150. Following the basal sample a mixture containing BCAA (E trial), or not containing BCAA (P trial) was ingested. In both trials no hormone basal concentrations, except insulin, were changed before exercise. In P trial, following exercise (sample 150), human growth hormone (HGH), prolactin (PRL), adrenocorticotropic hormone (ACTH) and cortisol (C) increased, while testosterone (T) decreased. In sample 210, after 1 h of rest, while ACTH, PRL and HGH had recovered to basal concentrations, C remained elevated and T displayed a further decrease. In the E trial a similar pattern of change was observed in sample 150 for HGH, PRL, ACTH and C; in sample 210 HGH and PRL displayed significantly lower values than in the corresponding P trial samples. The T was not modified by the running exercise and increased during the recovery period. It is, therefore, suggested that BCAA administration before exercise affects the response of some anabolic hormones, mainly HGH and T.
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The purpose of this study was to determine whether growth hormone (GH) administration enhances the muscle anabolism associated with heavy-resistance exercise. Sixteen men (21-34 yr) were assigned randomly to a resistance training plus GH group (n = 7) or to a resistance training plus placebo group (n = 9). For 12 wk, both groups trained all major muscle groups in an identical fashion while receiving 40 micrograms recombinant human GH.kg-1.day-1 or placebo. Fat-free mass (FFM) and total body water increased (P less than 0.05) in both groups but more (P less than 0.01) in the GH recipients. Whole body protein synthesis rate increased more (P less than 0.03), and whole body protein balance was greater (P = 0.01) in the GH-treated group, but quadriceps muscle protein synthesis rate, torso and limb circumferences, and muscle strength did not increase more in the GH-treated group. In the young men studied, resistance exercise with or without GH resulted in similar increments in muscle size, strength, and muscle protein synthesis, indicating that 1) the larger increase in FFM with GH treatment was probably due to an increase in lean tissue other than skeletal muscle and 2) resistance training supplemented with GH did not further enhance muscle anabolism and function.
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To examine endogenous anabolic hormonal responses to two different types of heavy resistance exercise protocols (HREPs), eight male and eight female subjects performed two randomly assigned protocols (i.e. P-1 and P-2) on separate days. Each protocol consisted of eight identically ordered exercises carefully designed to control for load, rest period length, and total work (J) effects. P-1 utilized a 5 RM load, 3-min rest periods and had lower total work than P-2. P-2 utilized a 10 RM load, 1-min rest periods and had a higher total work than P-1. Whole blood lactate and serum glucose, human growth hormone (hGH), testosterone (T), and somatomedin-C [SM-C] (i.e. insulin-like growth factor 1, IGF-1) were determined pre-exercise, mid-exercise (i.e. after 4 of the 8 exercises), and at 0, 5, 15, 30, and 60 min post-exercise. Males demonstrated significant (p less than 0.05) increases above rest in serum T values, and all serum concentrations were greater than corresponding female values. Growth hormone increases in both males and females following the P-2 HREP were significantly greater at all time points than corresponding P-1 values. Females exhibited significantly higher pre-exercise hGH levels compared to males. The P-1 exercise protocol did not result in any hGH increases in females. SM-C demonstrated random significant increases above rest in both males and females in response to both HREPs.(ABSTRACT TRUNCATED AT 250 WORDS)
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To examine endogenous anabolic hormone and growth factor responses to various heavy resistance exercise protocols (HREPs), nine male subjects performed each of six randomly assigned HREPs, which consisted of identically ordered exercises carefully designed to control for load [5 vs. 10 repetitions maximum (RM)], rest period length (1 vs. 3 min), and total work effects. Serum human growth hormone (hGH), testosterone (T), somatomedin-C (SM-C), glucose, and whole blood lactate (HLa) concentrations were determined preexercise, midexercise (i.e., after 4 of 8 exercises), and at 0, 5, 15, 30, 60, 90, and 120 min postexercise. All HREPs produced significant (P less than 0.05) temporal increases in serum T concentrations, although the magnitude and time point of occurrence above resting values varied across HREPs. No differences were observed for T when integrated areas under the curve (AUCs) were compared. Although not all HREPs produced increases in serum hGH, the highest responses were observed consequent to the H10/1 exercise protocol (high total work, 1 min rest, 10-RM load) for both temporal and time integrated (AUC) responses. The pattern of SM-C increases varied among HREPs and did not consistently follow hGH changes. Whereas temporal changes were observed, no integrated time (AUC) differences between exercise protocols occurred. These data indicate that the release patterns (temporal or time integrated) observed are complex functions of the type of HREPs utilized and the physiological mechanisms involved with determining peripheral circulatory concentrations (e.g., clearance rates, transport, receptor binding). All HREPs may not affect muscle and connective tissue growth in the same manner because of possible differences in hormonal and growth factor release.
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Supplemental dietary arginine HCl (ARG-HCl) minimizes immediate post-wounding weight loss, accelerates wound healing, and is thymotropic for uninjured and wounded rats. The present experiments were to determine if arginine-pituitary interactions underlie these effects because arginine is a growth hormone secretagogue. Effects of 1% dietary ARG-HCl supplements (0.5% added to a regular commercial rat diet containing 1.8% ARG, 0.5% in drinking water) were studied in (a) hypophysectomized (hypox) rats supplemented with ACTH, L-thyroxine, testosterone propionate, (b) such hypox rats additionally supplemented with bovine growth (hypox + bGH) hormone, (c) intact rats (Int), and (d) intact rats supplemented with growth hormone (Int. bGH). Group (a) hypox rats healed their wounds as rapidly as intact rats (dorsal skin incision breaking strength, accumulation of reparative collagen in sc polyvinyl alcohol sponges). Group (b) hypox, bGH rats showed increased wound breaking strength and accumulation of reparative collagen in the sc sponges to levels significantly greater than those of intact controls; bGH given to intact controls did not affect these indices of wound healing. Supplemental ARG-HCl given intact rats significantly minimized immediate postoperative weight loss, increased wound breaking strength and sponge reparative collagen accumulation, and increased thymic weight. None of these effects of supplemental ARG-HCl were observed in group (a) hypox rats or group (b) hypox + bGH rats. We conclude that an intact hypothalamic-pituitary axis is necessary for these beneficial effects of supplemental ARG-HCl given wounded rats.
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The effect of recombinant GH on strength, body composition and endocrine parameters in power athletes was investigated in a controlled study. Twenty-two healthy, non-obese males (age 23.4 +/- 0.5 years; ideal body weight 122 +/- 3.1%, body fat 10.1 +/- 1.0%; mean +/- SEM) were included. Probands were assigned in a double-blind manner to either GH treatment (0.09U (kg BW)-1 day-1 sc) or placebo for a period of six weeks. To exclude concurrent treatment with androgenic-anabolic steroids urine specimens were tested at regular intervals for these substances. Serum was assayed for GH, IGF-I, IGF-binding proteins, insulin and thyroxine before the onset of the study and at two-weekly intervals thereafter. Maximal voluntary strength of the biceps and quadriceps muscles was measured on a strength training apparatus. Fat mass and lean body mass were derived from measurements of skinfolds at ten sites with a caliper. For final evaluation only data of those 8 and 10 subjects in the two groups who completed the study were analyzed. GH, IGF-I and IGF-binding protein were in the normal range before therapy and increased significantly in the GH-treated group. Fasting insulin concentrations increased insignificantly and thyroxine levels decreased significantly in the GH-treated probands. There was no effect of GH treatment on maximal strength during concentric contraction of the biceps and quadriceps muscles. Body weight and body fat were not changed significantly during treatment. We conclude that the anabolic, lipolytic effect of GH therapy in adults depends on the degree of fat mass and GH deficiency.(ABSTRACT TRUNCATED AT 250 WORDS)
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Nine eumenorrheic women (age 24.11 +/- 4.28 yr) performed each of six randomly assigned heavy-resistance protocols (HREPs) on separate days during the early follicular phase of the menstrual cycle. The HREPs consisted of two series [series 1 (strength, S) and series 2 (hypertrophy, H)] of three protocols, each using identically ordered exercises controlled for load [5 vs. 10 repetitions maximum (RM)], rest period length (1 vs. 3 min), and total work (J) within each three-protocol series. Blood measures were determined pre-, mid- (after 4 of 8 exercises), and postexercise (0, 5, 15, 30, 60, 90, 120 min and 24 and 48 h). In series 1, a significant (P < 0.05) reduction in growth hormone (GH) was observed at 90 min postexercise for all three protocols. In series 2, the 10-RM protocol with 1-min rest periods (H10/1) produced significant increases above rest in GH concentrations at 0, 5, and 15 min postexercise, and the H10/1 and H5/1 protocols demonstrated significant reductions at 90 and 120 min postexercise. Cortisol demonstrated significant increases in response to the S10/3 protocol at 0 min, to the H10/1 protocol at midexercise and at 0 and 5 min postexercise, and to the H5/1 protocol at 5 and 15 min postexercise. No significant changes were observed in total insulin-like growth factor I, total testosterone, urea, or creatinine for any of the HREPs. Significant elevations in whole blood lactate and ammonia along with significant reductions in blood glucose were observed. Hormonal and metabolic blood variables measured in the early follicular phase of the menstrual cycle varied in response to different HREPs. The most dramatic increases above resting concentrations were observed with the H10/1 protocol, indicating that the more glycolytic HREPs may stimulate greater GH and cortisol increases.
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We examined gender differences in growth hormone (GH) secretion during rest and exercise. Eighteen subjects (9 women and 9 men) were tested on two occasions each [resting condition (R) and exercise condition (Ex)]. Blood was sampled at 10-min intervals from 0600 to 1200 and was assayed for GH by chemiluminescence. At R, women had a 3.69-fold greater mean calculated mass of GH secreted per burst compared with men (5.4 ± 1.0 vs. 1.7 ± 0.4 μg/l, respectively) and higher basal (interpulse) GH secretion rates, which resulted in greater GH production rates and serum GH area under the curve (AUC; 1,107 ± 194 vs. 595 ± 146 μg ⋅ l ⁻¹ ⋅ min, women vs. men; P = 0.04). Compared with R, Ex resulted in greater mean mass of GH secreted per burst, greater mean GH secretory burst amplitude, and greater GH AUC (1,196 ± 211 vs. 506 ± 90 μg ⋅ l ⁻¹ ⋅ min, Ex vs. R, respectivley; P < 0.001). During Ex, women attained maximal serum GH concentrations significantly earlier than men (24 vs. 32 min after initiation of Ex, respectively; P = 0.004). Despite this temporal disparity, both genders had similar maximal serum GH concentrations. The change in AUC (adjusted for unequal baselines) was similar for men and women (593 ± 201 vs. 811 ± 268 μg ⋅ l ⁻¹ ⋅ min), but there were significant gender-by-condition interactive effects on GH secretory burst mass, pulsatile GH production rate, and maximal serum GH concentration. We conclude that, although women exhibit greater absolute GH secretion rates than men both at rest and during exercise, exercise evokes a similar incremental GH response in men and women. Thus the magnitude of the incremental secretory GH response is not gender dependent.
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Five throwers from the Australian Institute of Sport volunteered to participate in this study. These athletes undertook a weight training circuit after being assigned to a pre-determined diet and amino acid supplement program. Each athlete took part in six programs (one per week), each program varying with regard to diet, amino acid and placebo intake. The purpose of this study was to investigate the effect of the interaction of diet, amino acid supplements and exercise on the release of growth hormone (GH). Of the six programs used, exercising in the fasted state resulted in a sevenfold increase in GH release over a program where food was eaten before exercising. The addition of amino acid supplements did not significantly enhance the release of GH under specified dietary conditions. Training in the fasted state would appear to optimise the release of GH.
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The contention that amino acids increase secretion of homan growth hormone has served as the catalyst for their increased popularity. Although growth hormone has been linked to muscle hypertrophy and its secretion is known to increase with exercise, there is no proof that artificially induced increases combined with weight training contribute to gains in strength and hypertrophy. further, growth-hormone-induced hypertrophy, as seen in acromegaly, does not follow the same process as work-induced muscle growth. It is possible that growth-hormone-induced muscle hypertrophy lacks corresponding strength properties because of increases in noncontractile protein. Additional research is needed to determine what effect, if any, combining amino acid supplementation with weight training has on muscle strength and hypertrophy.
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Stimulation of GH response to aminoacids infusion is well established. The ornithine chloride infusion (12 g/m2 within 30 min) induces an elevated peak of GH at a faithful time of 45 minutes. This test performed in 50 children with constitutional short stature showed the following results :In pituitary dwarfs no elevation of GH and cortisol was observed.In conclusion these data show that GH and cortisol levels mesured at zero and 45 min of ornithine infusion test allow to study simultaneously somatotropic and corticotropic pituitary functions.
Article
The serum growth hormone (GH) response of 6 non-weight-trained (NWT) and 6 weight-trained (WT) eumenorrehic, ovulatory women performing a heavy resistance exercise protocol (HREP) in the early follicular phase was examined. The HREP consisted of 7 different exercises and utilized a moderate resistance (10 repetition maximum) with short rest periods (1 minute). GH was evaluated preexercise, immediately postexercise, and 5, 15, 30, and 60 minutes postexercise. A significant difference was observed between groups (n = 6) for GH at preexercise, immediately, and 5 minutes postexercise (p < 0.05). The integrated area under the curve (AUC) for GH revealed no significant difference between groups (n = 6). However, after removing 2 subjects who were outliers (n = 5), significant differences in both the GH response over time (p < 0.01) and AUC GH (p < 0.01) were observed between groups. The most notable findings were that WT women demonstrated lower preexercise GH concentrations than their NWT counterparts with all subjects (n = 6; WT 2.47 +/- 1.27 [mu]g [middle dot] L-1; NWT 4.99 +/- 1.23 [mu]g [middle dot] L-1, p < 0.01) and with the removal of outliers (n = 5; WT 1.21 +/- 0.21 [mu]g [middle dot] L-1; NWT 4.08 +/- 1.0 [mu]g [middle dot] L-1 p < 0.01). Additionally, the HREP elicited a greater overall GH response in the WT group (n = 5; WT 179.6 +/- 59.5 [mu]g [middle dot] L-1; NWT-15.1 +/- 16.7 [mu]g [middle dot] L-1) as reflected by the integrated AUC (p < 0.01). The lower preexercise GH concentrations and greater overall GH response of the WT group suggest that, in women, GH response to resistance exercise varies with training status. (C) 2000 National Strength and Conditioning Association
Article
Aging is associated with a reduction in plasma growth hormone (GH) secretion in non-obese subjects. To determine whether or not age-related changes in plasma GH secretion exist in obese subjects, we measured (a) plasma GH response to growth hormone-releasing hormone (GRH; 1 μg/kg body wt), arginine (0.5 g/kg body wt), l-dopa (500mg), and (b) plasma glucose, insulin, and free fatty acids (FFAs) in 26 fasted obese subjects of various ages ranging from 16 to 71 years. Only subjects with a body mass index (BMI; kg/m2) between 30.0 and 39.0 were studied. Six subjects were adolescents, 9 were in their 20s, and 11 were 30 years or older. The mean peak levels of plasma GH in response to GRH, arginine, and l-dopa in obese subjects were 11.3 ± 2.1, 21.9 ± 4.4, and 5.2 ± 0.3 ng/mL in adolescents, 8.2 ± 1.6, 9.1 ± 1.5, and 3.1 ± 0.6 ng/mL in those in their 20s, and 4.5 ± 0.4, 7.3 ± 1.4, and 2.8 ± 0.3 ng/mL in those 30 years or older, respectively, showing a significant decrease in peak GH level with advancing age (P < .05 to P < .01). There was a negative correlation between the logarithmic increase in age and the peak GH response to GRH (r = −.635, P < .01), arginine (r = −.564, P < .01), and l -dopa (r = −.630, P < .01), and between the logarithmic increase in age and the integrated GH response to GRH (r = −.564, P < .01), arginine (r = −.612, P < .01), and l-dopa (r = −.551, P < .01) in all subjects. Plasma glucose, insulin, and FFAs did not change with age. There was no correlation between the peak GH level or the integrated GH response to these three stimuli and the plasma levels of glucose, insulin, and FFAs, respectively. Our findings suggest that in obese subjects advancing age reduces the secretory responsiveness of pituitary somatotropes to these three stimuli.
Article
Amino acid supplements are popular among bodybuilders because of unproven, yet attractive claims that pharmacologic dosages can elicit the release of growth hormone, an anabolic substance. Three female and nine male bodybuilders in training served as subjects. After an overnight fast, subjects were administered 40, 100 or 170 mg·kg−1 L-ornithine hydrochloride by mouth (oral route) in a random fashion over three successive Saturdays. Blood samples were drawn at baseline (T=0), 45 and 90 minutes post-administration. Regardless of dosage, mean 45 and 90 minute values for serum ornithine level were significantly (p<0.01) greater than baseline (T=0) values. Mean serum growth hormone levels tended to rise with ornithine ingestion, but only rose significantly (p<0.05) at 90 minutes post-administration at the 170 mg·kg−1 dosage. The findings indicate that oral ornithine is absorbed and systemic blood levels rise as a direct function of intake level. However, only at the highest dosage did ornithine elicit a predictable rise in serum growth hormone level.
Article
The purpose of this study was to compare serum growth hormone (GH), testosterone (T), cortisol (C), and whole blood lactate (L) responses to single set (1S) versus multiple set (3S) heavy-resistance exercise protocols. Eight recreationally weight-trained men completed two identical resistance exercise workouts (1S vs. 3S). Blood was obtained preexercise (PRE), immediately postexercise (OP), and 5 min (5P), 15 min (15P), 30 min (30P) and 60 min (60P) postexercise and was analyzed for GH, T, C, and L levels. For 1S and 3S, GH, L, and T significantly increased from PRE to OP and remained significantly elevated to 60P, except for 1S. For GH, T, and L, 3S showed significantly greater increases compared to 1S. For C, 3S and 1S were increased significantly from resting at OP, 5P, and 15P; 3S increased compared to 1S at 5P, 15P and 30P. Higher volumes of total work produce significantly greater increases in circulating anabolic hormones during the recovery phase following exercise.
Article
1. Six well-trained cyclists and six untrained subjects were studied during and immediately after four successive 7 min periods of exercise at 30, 45, 60 and 75% of their maximal work capacity. 2. Venous blood samples were taken at rest, at the end of each exercise period and 5 min following the end of exercise, for estimation of metabolites in blood and plasma insulin, growth hormone, cortisol and catecholamines. 3. The results showed significant differences in the mobilization and utilization of muscle fuels between the athletically fit cyclists and the untrained group. In the cyclists, glucose, glycerol and free fatty acid concentrations were higher, but lactate, pyruvate and alanine were lower than in the untrained subjects during exercise. 4. Plasma catecholamines rose in both groups during exercise but the rise was significantly less in the racing cyclists. Plasma insulin was depressed to a greater extent in the untrained subjects during exercise and plasma glucagon rose to a greater extent during strenuous exercise and remained elevated after the end of exercise in the untrained group. Plasma human growth hormone rose to a greater extent during exercise and remained elevated after the end of exercise in the untrained group. Plasma cortisol fell at low and moderate exercise rates in both groups, but to a smaller extent in the cyclists. Cortisol values rose at higher workloads and were significantly higher in the cyclists at the end of exercise. 5. It is concluded that there are significant differences in the metabolic and hormonal responses to exercise between athletically trained and untrained individuals, even when the physically fit subjects work at the same percentage of their maximal capacity as the unfit subjects.
Article
This study was designed to compare the serum growth hormone (GH) response with quantified exercise to that obtained with other stimuli. In eight normal males, aged 21-24 yr, we studied the serum GH response to 20 min cycle ergometer exercise at 300, 600, and 900 kpm/min on three separate occasions and compared the results with those found during sleep, insulin hypoglycemia, arginine infusion, and L-DOPA. Exercise at 900 kpm/min and insulin hypoglycemia resulted in the greatest elevations in serum GH which were significantly greater than those found with sleep, arginine or L-DOPA. The 20-min exercise at 900 kpm/min represented 75-90% of the subjects' maximal oxygen uptake and is a suitable provocative test for GH secretion. As a screening test for pituitary GH reserve, exercise compares favorably with insulin hypoglycemia and is superior to sleep, arginine, and L-DOPA.
Article
It has been suggested that growth hormone (GH), testosterone (T), and insulin-like growth factor I (IGF-I) play large roles in muscle tissue growth; however, in only two investigations IGF-I responses to resistive exercise have been examined. Eight young males who had not weight trained for a minimum of 5 months participated in the study. Three sets of bench press (BP), lat-pull (LP), leg extension (LE), and leg curl (LC) exercises were performed at a 10-RM load for 10 repetitions or until failure. Blood samples were collected from an IV catheter before exercise (-30 min and -10 min), after each individual exercise (BP, LP, LE, LC), and after the exercise session (+5, +15, +25, +35, +95 min; +5:35, +22:30, and +23:30 h). GH, IGF-I, and T determinations were corrected for plasma volume change. GH significantly increased (P < 0.05), but IGF-I did not change. Correction for plasma volume accounted for significant increases in T, but did not account for GH and IGF-I results. These data suggest that moderate resistive exercise may increase GH concentrations, whereas elevated T levels can be accounted for by exercise-induced alteration of plasma volume.
Article
Whereas the lipolytic and diabetogenic consequences of sustained growth hormone (GH) exposure are well described, the metabolic effects of a short-lived physiological GH pulse have only recently been reported. To assess the possible dose-response of such short-term bolus administration of GH, six healthy, male subjects were each studied thrice for 4 1/2 hours after an intravenous (IV) bolus of either 70, 140, or 350 micrograms GH, resulting in peak GH concentrations of 10, 15, and 34 micrograms/L. Observed results include: (1) Time- (but not dose-) dependent changes (P less than .05) in plasma glucose and an acute (from 10 minutes onward), persistent, 40% decrease in forearm glucose uptake. Total glucose turnover decreased steadily with time on all occasions. (2) Time- and dose-dependent increases (P less than .05) in the concentrations of circulating lipid intermediates, with an increase of 3-hydroxybutyrate (3-OHB) from a basal of 35 mumol/L to peak values of 108 +/- 34 (70 micrograms), 176 +/- 46 (140 micrograms), and 232 +/- 51 mumol/L (350 micrograms), forearm uptake of 3-OHB changed in parallel. (3) Respiratory exchange ratio decreased (P less than .05) with increasing GH doses (indicating increased lipid and decreased glucose oxidation), and energy expenditure remained unaffected. (4) Concentrations of insulin, C-peptide, and glucagon were unchanged throughout all studies. We conclude that the stimulating effects of a modest GH bolus on circulating lipid intermediates and lipid oxidation are dose-dependent. This finding underlines the potential role of GH as a principal physiological regulator of fuel consumption in the maintenance of metabolic homeostasis.
Article
Using double-blind, placebo-controlled procedures, the effects of low and high therapeutic dosages of methionyl-human growth hormone (met-hGH) on body composition, muscle protein metabolism and serum lipids were studied in 7 fit adults without growth hormone (GH) deficiency. Dose-dependent changes in body composition were observed that in part appeared to be influenced by a response-recovery effect, as measured by responses factored according to the duration of washout between exposure to the low and high dosages of met-hGH (6 weeks vs. 12 weeks vs. 18 weeks). Increases in fat-free weight were accompanied by an increase in skeletal muscle protein metabolism. Basal levels of cholesterol were inversely related to peak levels of GH in response to exercise stimulation and IGF-I, while GH supplementation lowered levels of total cholesterol and high- and low-density lipoproteins. A dose-dependent effect occurred for total cholesterol, and the percent change in cholesterol was related to the percent change in insulin-like growth factor I (IGF-I). Endogenous levels of GH were attenuated in response to stimulation and IGF-I levels were increased after treatment with GH, but no dose-dependent changes were observed. We conclude that met-hGH alters body composition and muscle protein metabolism, and decreases stored and circulating lipids in fit adults with a pre-existing supranormal body composition. The physiological profile of the person was not as important as the treatment conditions in determining the somatic and physiological response outcomes.
Article
The effects of several neurotransmitter amino acids on pituitary hormone secretion were examined in normal humans. Oral administration of 10 g of glutamic acid stimulated the secretion of prolactin (PRL) and cortisol to approximately twice baseline values, with no effect on GH, TSH or LH. Aspartic acid (10 g), taurine (5 g), and cysteine (5 or 10 g) had no consistent effect on any hormone measured, although the lack of effect of aspartic acid may relate to the modest increments in serum concentration achieved. Glutamic acid may be an important modulator of PRL and ACTH secretion in humans.
Article
The effects on lipid metabolism of a single intramuscular dose of SR 29001 (0.15 U/kg body wt), a biosynthetic human growth hormone (hGH), were explored in a double-blind randomized crossover vs a placebo study of six normal-weight and six obese subjects (Quetelet Index greater than 120%). Circulating hGH concentrations reached means of 35 and 28 ng/mL in the normal-weight and obese subjects, respectively. Free fatty acids increased in both groups (p less than 0.05); increases in beta-hydroxybutyrate and acetoacetate concentrations were more moderate (NS). Plasma glucose increased significantly despite a significant increase in insulin (p less than 0.002). The lipolytic effect persisted after a standardized 950-kcal meal eaten 5 h after hGH administration. A delayed increase in somatomedin-C and decreases in blood urea and total cholesterol were also observed (p less than 0.05). Despite increased insulin secretion, biosynthetic hGH produced a significant increase of lipolysis in both groups, which was only partially suppressed by food.
Article
Twenty-two adult males participated in a 5 week progressive strength training program. One half the subjects received the amino acids L-arginine and L-ornithine and the other half, a placebo. The study used a double blind protocol so that subjects as well as investigators had no knowledge of which substances were being administered. Dosages amounted to 2 grams or 1 gram each of L-arginine and L-ornithine, and 600 mg of calcium and 1 gram of Vitamin C as placebos. These supplements were taken orally for a total of 25 administrations. Following the short term strength program using progressively high intensities, tests were taken for total strength (TS), lean body mass (LBM) and urinary hydroxyproline (UH). The results from ANOVA showed that subjects who were taking the arginine-ornithine combination scored significantly higher in TS and LBM (p less than .05), and significantly lower in UH (p less than .05), than subjects on placebos. It was concluded that arginine and ornithine taken in prescribed doses can, in conjunction with a high intensity strength training program, increase TS and LBM in a relatively short period of time. Arginine and ornithine also aid in recovery from chronic stress by quelling tissue breakdown as evidenced by lower UH levels.
Article
To determine how arginine (Arg) stimulates GH secretion, we investigated its interaction with GHRH in vivo and in vitro. Six normal men were studied on four occasions: 1) Arg-TRH, 30 g arginine were administered in 500 mL saline in 30 min, followed by an injection of 200 μg TRH; 2) GHRH-Arg-TRH, 100 μg GHRH-(1-44) were give iv as a bolus immediately before the Arg infusion, followed by 200 μg TRH, iv; 3) GHRH test, 100 μg GHRH were given as an iv bolus; and 4) TRH test, 200 μg TRH were given iv as a bolus dose. Blood samples were collected at 15-min intervals for 30 min before and 120 min after the start of each infusion. Anterior pituitary cells from rats were coincubated with Arg (3, 6, 15, 30, and 60 mg/mL) and GHRH (0.05, 1, 5, and 10 nmol/L) for a period of 3 h. Rat GH was measured in the medium. After Arg-TRH the mean serum GH concentration increased significantly from 0.6 to 23.3 ± 7.3 (±SE) μg/L at 60 min. TRH increased serum TSH and PRL significantly (maximum TSH, 11.1 ± 1.8 mU/L; maximum PRL, 74.6 ± 8,4 μg/L). After GHRH-Arg-TRH, the maximal serum GH level was significantly higher (72.7 ± 13.4 μg/L) than that after Arg-TRH alone, whereas serum TSH and PRL increased to comparable levels (TSH, 10.2 ± 3.0 mU/L; PRL, 64.4 ± 13.6 μg/L). GHRH alone increased serum GH to 44.9 ± 9.8 μg/L, significantly less than when GHRH, Arg, and TRH were given. TRH alone increased serum TSH to 6.6 ± 0.6 mU/L, significantly less than the TSH response to Arg-TRH. The PRL increase after TSH only also was lower (47.2 ± 6.8 μg/L) than the PRL response after Arg-TRH. In vitro Arg had no effect on basal and GHRH-stimulated GH secretion. Our results indicate that Arg administered with GHRH led to higher serum GH levels than did a maximally stimulatory dose of GHRH or Arg alone. The serum TSH response to Arg-TRH also was greater than that to TRH alone. We conclude that the stimulatory effects of Arg are mediated by suppression of endogenous somatostatin secretion.
Article
The data provide evidence that human growth hormone increases more rapidly after maximal and sub-maximal exercise following high fat diet in comparison with high CHO diet. A decrease in the plasma concentrations of FFA after high CHO diet is associated with lower concentrations of HGH compared with the values obtained at the end of maximal and sub-maximal exercise after high fat diet.
Article
The effects of biosynthetic methionyl-human growth hormone (met-hGH) on body composition and endogenous secretion of growth hormone (GH) and insulin-like growth factor I (IGF-I) were studied in eight well-trained exercising adults between 22 and 33 yr of age. By the use of double-blind procedures, met-hGH (2.67 mg/0.5 ml diluent, 3 days/wk) and bacteriostatic water (placebo, 0.5 ml, 3 days/wk) were administered in a repeated-measures design that counterbalanced treatment order. Duration of each treatment was 6 wk. Subjects trained with progressive resistance exercise throughout and were maintained on a high-protein diet monitored by extensive compositional analyses of daily dietary intake records. Hydrodensitometry revealed that met-hGH significantly decreased percent body fat (%fat) and increased fat-free weight (FFW) and FFW/fat weight (FW), whereas the placebo treatment did not change any of these measures. Changes in FFW/FW correlated with the relative dose of met-hGH but did not correlate with either the peak GH response to L-dopa/arginine stimulation or IGF-I levels obtained after treatment with placebo. There were no differences between treatments in the dietary intakes of total kilocalories, protein, carbohydrates, and fat. Mean IGF-I levels were elevated after treatment with met-hGH compared with postplacebo levels. After treatment with met-hGH, five of seven subjects had a suppressed GH response to stimulation from either L-dopa/arginine or submaximal exercise. We conclude that supraphysiological doses of met-hGH will alter body composition in exercising adults in a relative dose-dependent manner and that such treatment may suppress endogenous release of GH in some individuals.
Article
The balance between protein synthesis and breakdown (protein turnover) regulates whole-body protein mass. The relationships between dietary changes (amount and composition of food) and protein synthesis, protein breakdown and amino acid oxidation have been explored in order to better understand adaptations of protein and amino acid metabolism. Methods for measuring protein synthesis, especially whole-body protein synthesis, can be divided into two groups: the 15N end-product method (urea and/or ammonia), and the incorporation of labelled amino acid(s) into proteins. Assumptions and limitations of the widely used two-pool model (free amino acid and protein pools) are discussed. Results obtained with different methods and for amino acids have been compared, to assess their ability to detect changes in protein synthesis rates. Methods of measuring protein breakdown have also been described briefly. Food intake affects whole-body and tissue protein turnover throughout development of animals and humans in different ways. Protein metabolism fluctuates during the 24-hour period in response to intermittent food intake. During the post-prandial period, a net whole-body protein deposition occurs. This is essentially due to increased protein synthesis. The free amino acid pool and amino acid oxidation rates also increase. Consequently, amino acids are used to a great extent as energy substrates. In contrast, a decrease in protein breakdown could enhance protein deposition. During fasting, the rates of whole-body protein synthesis are lower than those of protein breakdown. This results in protein loss, essentially because the drop in protein synthesis rate in muscle is pronounced. N balance is controlled by the amounts and composition of the diet and by changes in protein synthesis and breakdown. Increasing food intake above levels of energy equilibrium can produce growth by enhancing both the whole-body protein synthesis and breakdown rates. Below energy equilibrium, whole-body protein loss occurs because of decreased protein synthesis which becomes lower than protein breakdown. Protein synthesis rate is the main factor controlling N balance in response to alterations in food intake. Increasing dietary protein, especially the essential amino acids, involves increased rates of whole-body protein synthesis and breakdown. The improved N balance obtained by enhancing dietary non-protein energy (carbohydrate, fat) can be brought on by reducing amino acid oxidation and slightly increasing protein synthesis. The effects of dietary protein and energy on protein turnover are apparently additive.
Article
Eighteen adult males took part in a double blind study investigating the effects of weight training and dietary supplementation of the nonessential amino acid arginine and ornithine on body mass, body fat and composite body girth. The results showed significant differences in body mass and body fat (p < .01) in the group taking amino acids as compared to the group taking placebos. There was no significant difference in composite body girth. Resistance exercise with a diet supplemented with arginine and ornithine will reduce body mass and body fat in adult males.