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Plasma levels of trace elements and exercise induced stress hormones in well-trained athletes
Abstract
This study analyzed the variation and relationship of several trace elements, metabolic substrates and stress hormones activated by exercise during incremental exercise. Seventeen well-trained endurance athletes performed a cycle ergometer test: after a warm-up of 10min at 2.0Wkg(-1), the workload was increased by 0.5Wkg(-1) every 10min until exhaustion. Prior diet, activity patterns, and levels of exercise training were controlled, and tests timed to minimize variations due to the circadian rhythm. Oxygen uptake, blood lactate concentration, plasma ions (Zn, Se, Mn and Co), serum glucose, non-esterified fatty acids (NEFAs) and several hormones were measured at rest, at the end of each stage and 3, 5 and 7min post-exercise. Urine specific gravity was measured before and after the test, and participants drank water ad libitum. Significant differences were found in plasma Zn and Se levels as a function of exercise intensity. Zn was significantly correlated with epinephrine, norepinephrine and cortisol (r=0.884, P<0.01; r=0.871, P<0.01; and r=0.808, P=0.05); and Se showed significant positive correlations whit epinephrine and cortisol (r=0.743, P<0.05; and r=0.776, P<0.05). Neither Zn nor Se levels were associated with insulin or glucagon, and neither Mn nor Co levels were associated with any of the hormones or substrate metabolites studied. Further, while Zn levels were found to be associated only with lactate, plasma Se was significantly correlated with lactate and glucose (respectively for Zn: r=0.891, P<0.01; and for Se: r=0.743, P<0.05; r=0.831, P<0.05). In conclusion, our data suggest that there is a positive correlation between the increases in plasma Zn or Se and stress hormones variations induced by exercise along different submaximal intensities in well-hydrated well-trained endurance athletes.
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... However, this delicate balance is subject to continuous vital changes arising from the enzymatic system activated by minerals and trace elements [2]. Therefore, it is important to examine the effects of exercise on the element metabolism [3]. While some studies suggest that physical exercise affects the element metabolism [3], there are also others demonstrating that the urinary element levels of athletes did not change after acute exercise [4]. ...
... Therefore, it is important to examine the effects of exercise on the element metabolism [3]. While some studies suggest that physical exercise affects the element metabolism [3], there are also others demonstrating that the urinary element levels of athletes did not change after acute exercise [4]. However, when it was reported that severe physical exercises could change the trace element metabolism, leading to the suppression of the immune system and to infections [5], the subject started to attract more attention in terms of not only performance but also athlete health. ...
... Recently, these compounds have been enjoying growing interest in medical research. In this group, the most commonly studied polyphenol is resveratrol (3,5,4,trihydroxystilbene), found abundantly in grapes and berries [7]. Resveratrol is naturally present in some food and drinks including grapes and red wine [8]. ...
The aim of the present study is to examine how resveratrol administration affects the element metabolism in the blood and brain cortex tissues of rats subjected to an acute swimming exercise. The study was carried out on Wistar-Albino-type adult male rats supplied by the Center. Group 1 is the control group. Group 2 is the swimming control group. Group 3 is the resveratrol (10 mg/kg/day) + swimming group. Group 4 is the resveratrol (10 mg/kg/day) group. Blood and brain cortex tissues were analyzed for some elements. The acute swimming exercise led to increases in the rats’ serum iron, selenium, lead, cobalt, and boron levels, while the resveratrol-swimming group has increases in copper, phosphorus, and calcium values. The brain cortex tissue of the resveratrol-swimming group had significantly higher molybdenum levels than others. The results obtained in the study indicate that acute swimming exercise altered the distribution of elements in the serum to a considerable extent; however, resveratrol’s affect is limited. Especially, resveratrol supplementation may have a regulatory affect on serum iron and magnesium levels.
... Regular exercise training or increased physical activity has favourable effects on many established risk factors for metabolic or cardiovascular disease (1,2). However, exercise induced metabolic stress causes many challenge in body homeostasis and may have effects on oxidative balance and trace elements (3,4). Many sedentary people are involved in various type of physical activity to improve their health. ...
... In the present study we did not found any correlation between change in MDA and TAC, reflecting metabolic and oxidative stress conditions, and Zn levels in all soccer matches in sedentary subjects. However, a positive correlation between increases in Zn and exercise induced stress hormones variations in well trained athletes (3). ...
Objective: We aimed to examine effects of soccer match induced metabolic stress on levels of some trace elements. Materials and Methods: Fourteen sedentary male subjects randomly performed three indoor soccer matches (2 x 30 minute) in morning, afternoon and at night on different days. Venous blood samples were taken before and after match. Plasma malondialdehyde levels measured by High Performance Liquid Chromatography. Total antioxidant capacity and total oxidant capacity were estimated using a commercially available enzyme-linked immunosorbent assay kit. Plasma iron, copper and zinc levels was measured using an Atomic Absorption Spectrophotometer. Results: Significant increases were found in iron, malondialdehyde and total oxidant capacity in all matches (p<0.0001). Zinc decreased (p<0.0001) in morning but increases at night soccer a match (p<0.0001) which is opposite to copper. Conclusions:There was no significant correlation between increased stress parameters and trace element levels. However, time of soccer match causes opposite influence on levels of zinc and copper.
... Vascular tone in vivo, to a great extent, is associated with the activation of the smooth muscle cell (SMC) a-adrenoceptors by adrenaline and noradrenaline releasing from the adrenal glands and reaching high levels in blood in a stressful situation (Borovsky et al. 1998;Pacak et al. 1998;Omerovic et al. 2000) and during exercise (Soria et al. 2015). Besides, under such conditions, the sympathetic nerve activity was increased (Ootsuka and McAllen 2005;Hudson et al. 2011;Boulton et al. 2019) leading to the a-adrenoceptors activation by noradrenaline released from sympathetic nerve endings. ...
... It is well known that the blood noradrenaline level might rise significantly under stress conditions and during exercise. Specifically, plasma noradrenaline concentration can reach 0.007 lmol/L under cold stress (Pacak et al. 1998), 0.025 lmol/L during heavy exercise (Soria et al. 2015), 0.04 lmol/L after myocardial infarction (Omerovic et al. 2000), and 0.13 lmol/L in rats exposed to CO 2 asphyxia (Borovsky et al. 1998). Thus, the potentiating effect of acidosis found in the present study occurs at physiologically relevant noradrenaline concentrations. ...
Although vasodilatation evoked by acidosis at normal body temperature is well known, the reports regarding effect of acidosis on the reactivity of the isolated arteries at low temperatures are nonexistent. This study tested the hypothesis that the inhibitory effect of acidosis on the neurogenic vasoconstriction may be increased by cooling. Using wire myography, we recorded the neurogenic contraction of the rat tail artery segments to the electrical field stimulation in the absence and in the presence of 0.03–10.0 µmol/L noradrenaline. The experiments were conducted at 37 °C or 25 °C and pH 7.4 or 6.6 which was decreased by means of CO2. Noradrenaline at concentration of 0.03–0.1 µmol/L significantly potentiated the neurogenic vasoconstriction at 25 °C, and the potentiation was not inhibited by acidosis. Contrary to our hypothesis, acidosis at a low temperature did not affect the noradrenaline-induced tone and significantly increased the neurogenic contraction of the artery segments in the absence and presence of noradrenaline. These effects of acidosis were partly dependent on the endothelium and L-type Ca²⁺ channels activation. The phenomenon described for the first time might be of importance for the reduction in the heat loss by virtue of decrease in the subcutaneous blood flow at low ambient temperatures.
... However, the frequency with which a physical or sports activity is carried out, as well as its level of intensity and type, plays an important role in the possible effects, be they beneficial or harmful, on the organism and health [5]. Sports, with the physical and emotional stress associated with a competitive environment, can modify the metabolism and alter the use and absorption of some micronutrients such as minerals and trace elements [6][7][8]. Endocrine changes, in the event that mineral homeostasis does not adapt correctly to the new circumstances, can lead to negative results in the performance and health of athletes [9]. This situation is even more relevant if physical exercise is done at the growing stage, in which the individual's body and emotional development have not yet been completed and so the body status of these micronutrients must be adequate. ...
... However, due to the limited number of studies on the influence of doing sport on Mn status, these types of observations are still inconclusive. Conversely, Soria et al. [6] in male triathletes have not found any significant differences in Mn plasma levels before and after performing an incremental maximal test. ...
This study evaluates the influence on body development of doing rhythmic gymnastics in girls from 10 to 17 years of age, the results of certain strength and flexibility abilities, and the trace element status (Ca, Fe, Zn, Cu, Mn, Cr, and Ni). The subjects were divided into three groups: (a) girls who practiced rhythmic gymnastics at a competition level (competition group); (b) girls who practiced this sport at a non-competitive level (training group); and (c) girls who do not practice any sport and with a low level of physical activity (control or sedentary group). Trace element status was determined in hair and urine samples. Results showed that doing rhythmic gymnastics does not alter the normal physical development of muscle mass, and even leads to a decrease in body fat content. Furthermore, better scores in the strength and flexibility test were obtained by the participants of this sports discipline. Statistically significant differences in urine Fe, Cu, and Mn values (p < 0.05) and in hair Cr, Cu, and Mn values (p < 0.05) were found between the two rhythmic gymnastics groups and the control group, and were higher in the competition and training groups. A principal component analysis model was performed to evaluate the possibility of cluster formation among the girls. The PCA results revealed a separation between the different groups although the separation was not perfect. PLS-DA was attempted in order to verify whether it was possible to discriminate between the groups included in this study. It was clear that the competition and control ones were very well classified (around 95% of correct predictions) but 20% of the girls belonging to the training group were misclassified as belonging to the competition one.
... The main exposure sources to TM is diet and air [8]. Significant interactions have been observed between TM levels and the endocrine system since TM influence the metabolism of hormones and vice versa, so changes in hormone concentrations could affect the metabolism and redistribution of TM [9]. ...
... As mentioned above, significant interactions have been observed between TM concentrations and the endocrine system. It is known that TM have biological implications for endocrine processes [23], and a large number of studies examine these relationships in animals or healthy subjects; however, few studies have examined the relationship between hormones and TM in athletes [9,15]. ...
The authors wish to correct the following erratum in this paper [...]
... The main exposure sources to TM is diet and air [8]. Significant interactions have been observed between TM levels and the endocrine system since TM influence the metabolism of hormones and vice versa, so changes in hormone concentrations could affect the metabolism and redistribution of TM [9]. ...
... As mentioned above, significant interactions have been observed between TM concentrations and the endocrine system. It is known that TM have biological implications for endocrine processes [23], and a large number of studies examine these relationships in animals or healthy subjects; however, few studies have examined the relationship between hormones and TM in athletes [9,15]. ...
Several essential trace minerals play an important role in the endocrine system; however, toxic trace minerals have a disruptive effect. The aim of this research was to determine basal concentrations and the possible correlations between trace minerals in plasma and several plasma hormones in runners. Sixty high-level male endurance runners (21 ± 3 years; 1.77 ± 0.05 m; 64.97 ± 7.36 kg) participated in the present study. Plasma hormones were analyzed using an enzyme-linked immunosorbent assay (ELISA) and plasma trace minerals were analyzed with inductively coupled plasma mass spectrometry (ICP-MS). Correlations and simple linear regression were used to assess the association between trace minerals and hormones. Plasma testosterone concentrations were inversely correlated with manganese (r = −0.543; β = −0.410; p < 0.01), selenium (r = −0.292; β = −0.024; p < 0.05), vanadium (r = −0.406; β = −1.278; p < 0.01), arsenic (r = −0.336; β = −0.142; p < 0.05), and lead (r = −0.385; β = −0.418; p < 0.01). Plasma luteinizing hormone (LH) levels were positively correlated with arsenic (r = 0.298; β = 0.327; p < 0.05) and cesium (r = 0.305; β = 2.272; p < 0.05), and negatively correlated with vanadium (r = −0.303; β = −2.467; p < 0.05). Moreover, cortisol concentrations showed significant positive correlations with cadmium (r = 0.291; β = 209.01; p < 0.05). Finally, insulin concentrations were inversely related to vanadium (r = −0.359; β = −3.982; p < 0.05). In conclusion, endurance runners living in areas with high environmental levels of toxic minerals should check their concentrations of anabolic hormones.
... The regulation of trace elements in blood and tissues should be kept within optimal limits to support metabolic functions of the body systems at rest at also during exercise (2). Importantly; physical exercise may cause redistribution of some trace elements between body stores, blood and tissues (2,3). ...
... This finding is in agreement with the results of several authors who observed no differences (15,35,37). The small but non-significant decrease in Zn levels after both soccer matches could be related with shift of Zn from blood to cell (3). Interestingly, there is no significant effect of soccer match on plasma Zn status in morning and at night. ...
The aim of this study was to comparatively evaluate effect of morning and nocturnal soccer matches induced metabolic stress on plasma levels of iron (Fe), copper (Cu) and zinc (Zn). Twenty male footballers performed two soccer matches in morning and at night on different days. Blood samples were taken before and after match. The levels of Fe, Zn and Cu were measured through an atomic absorption spectrophotometry. Metabolic stress was evaluated by altered malondialdehyde (MDA) levels that measured using High Performance Liquid Chromatography. In morning and at nocturnal soccer matches, levels of MDA (36% and 27%), Fe (37.4% and 38.9%) and Cu (34.8% and 26.8%) were all increased in all subjects, respectively. However, Zn level decreased-4.5 % in morning (n=10 subjects) and-9.4% at nocturnal (n=12 subjects) soccer matches. In addition, Cu/Zn ratio increased significantly 46.6% in morning and 36.6% at nocturnal soccer matches. Soccer match has significant effects on levels of MDA, Fe and Cu but not Zn levels. The results of this study showed that morning soccer match significantly alters levels of MDA and Cu and Cu/Zn ratio compared to nocturnal soccer match.
... Exercise brings about endocrinological changes to balance homeostasis during challenging coordinative movements, thus leading to physiological and psychological stress. It triggers a coordinated series of physiological responses which influence systems like the hypothalamus-pituitary-adrenal (HPA) axis and the sympathetic nervous system in particular, two of the basic stress activation systems (Soria et al., 2015;Furtado et al., 2016). ...
... Many studies have shown that in different species, exercise increases the level of cortisol (Kindermann et al., 1982;Farrell, 1989;Soria et al., 2015;Wingfield et al., 2015;Kayacan et al., 2016;Klentrou et al., 2016;Koutsandréou et al., 2016). However, data in the literature suggest that cortisol release varies with physiological activation parameters such as exercise intensity and duration and physical conditions (Filaire et al., 1996;Yazdanparast, 2009). ...
Cortisol is a corticosteroid hormone produced by the adrenal cortex and it is associated with the stress response of the body. It is an important marker for determining the level of stress during or after exercise. The purpose of this study was to examine a sports team for the level of physiological and psychological stress generated by a handball competition via non-invasive saliva analysis. Fourteen athletes aged 20.7 ± 2.5 years who were members of the Ondokuz Mayıs University male handball team participated in the study. A total of three saliva samples were taken, one before, one during half-time and one immediately after an important match for the team in terms of the group standpoint. and were analyzed by ELISA. Data were analysed by repeated measures test and Mauchly's test of sphericity; also p<0.05 denoted statistical significance. As a result of the analysis, salivary cortisol levels were found to be significant in the three different samples taken from the athletes (p = 0.018) At the onset of the ıy defferent competition, cortisol levels were also seen to increase in parallel with the rise in the stress levels of the athletes. The highest cortisol levels of the athletes were found in the samples taken between halves during the match. It was found that submaximal exercise used in the team sport of handball had a significant effect on salivary cortisol levels. In samples taken during an event with a high level of importance for the team, significantly variable levels of cortisol as a stress hormone were expressed in the athletes. Therefore, saliva cortisol measurement appears to be an important parameter that can be used to develop stress-management and other necessary strategies in sport branches such as handball where the mental and physical stress is intense.
... It also plays small roles in metabolism, attention, focus, panic, and excitement [38]. Epinephrine concentration enhances rapidly after doing physical activity [39] and it helps in the enhancement of mental concentration. Several studies conclude that physical aerobic activity is positively correlated with the level of epinephrine concentration in the human body so it will be helpful for the athletes who are engaging with that type of sport and it is also associated with extreme sports such as skydiving etc. to enhance focus, mood and outlook during play [40]. ...
Physical activity induces many changes in the human body by increasing energy metabolism and resting energy expenditure and hormones play a major role in these changes. Hormones are chemical messengers that stimulate biochemical reactions that trigger cell activity and functions. Hormones are secreted from the glands of the endocrine system and communication between the endocrine system and nervous system regulates both internal and external changes and maintains homeostasis. Hormones are classified into lipid, amino acid, and peptide-derived hormones and they play major roles in the human body. Lipid-derived hormones perform many important functions i.e., muscle growth, neuromuscular adaptation, protein metabolism, carbohydrate metabolism, gluconeogenesis, fat oxidation, salt and water homeostasis, etc. Amino acid-derived hormones also perform many important functions like vasoconstriction, thermoregulation, tissue differentiation, fight or flight response, maintaining circadian rhythm and sleep-wake cycle, etc. Peptide-derived hormones play a major role in body fluid homeostasis, regulating appetite, gluconeogenesis, glucose production, and lipid metabolism, maintaining circadian rhythm, maintaining energy balance, reducing weight gain, delaying gastric emptying, etc. Physical activity regulates hormone levels in the body to provide major benefits and enhance the health status of healthy individuals. This review will provide a brief description of all lipid, amino acid, and peptide-derived hormones that perform many important functions and how their functions are influenced by physical activity.
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... Adequate hydration during training or competition prevents dehydration, maintains optimal body temperature, and improves performance [6,7]. Reports show higher adrenaline levels in athletes following fluid consumption after dehydration than in those without fluid intake [1,19]. Therefore, the American College of Sports Medicine (ACSM) recommends that effective rehydration requires the intake of a greater volume of fluid (e.g., 125-150%) than the final fluid deficit (eg, 1.25-1.5 ...
Background
To verify the hydration effects of oral rehydration solution (ORS) on athletes by comparing the degrees of fluid absorption and plasma volume changes following beverage consumption, including ORS.
Methods
Thirty-one participants visited the testing laboratory 4 times at 1-week intervals to consume 1 L of beverage (e.g., water, ORS, and two sports drinks [SpD]) for 30 min on each visit. The urine output was measured 4 times at 1 h, 2 h, 3 h, and 4 h after beverage consumption. A blood sample was collected 3 times at 1 h, 2 h, and 3 h after beverage consumption. Body weight was measured once in 4 h after beverage consumption.
Results
Body weight change was smaller for ORS than for water, SpD1, and SpD2 ( p < 0.05). Cumulative urine output in 4 h was lower for ORS, SpD1, and SpD2 than for water ( p < 0.05), and it was lower for ORS than for SpD2 ( p < 0.05). BHI in 4 h was higher for ORS, SpD1, and SpD2 than for water ( p < 0.05), and it was higher for ORS than for SpD2 ( p < 0.05). There was no significant difference in PVC for different beverages at all test times, i.e.., 1 h, 2 h, and 3 h.
Conclusions
We evaluated the hydration effects of the consumption of beverages, such as water, SpD, and ORS in athletes. ORS and SpD were more effective than water. A comparison between ORS and SpD showed that the result could vary depending on the type of SpD.
... Soccer is an anaerobic-aerobic sport where sprints, acceleration, deceleration, changes of direction, and trauma are prevalent [65]. Consequently, these actions lead to increased muscle damage, and increased protein and amino acid catabolism, which could induce a higher release of Zn from muscle cells to plasma, since most Zn concentrations mainly predominate in skeletal muscle [2,21,66]. Elsewhere, Rodriguez-Tuya et al. [16] reported that anaerobic athletes (judo and fencing) had higher plasma Zn concentrations due to the lower role of the antioxidant system and energy metabolism, where Zn acts as an enzyme cofactor, in anaerobic modalities. As an adaptation, aerobic training could increase Zn entry into the cell to promote metalloprotein synthesis, triggering lower plasma Zn concentrations [54]. ...
Background:
Physical exercise affects zinc (Zn) homeostasis. This study aimed to analyze the influence of physical training on extracellular (serum, plasma, and urine) and intracellular (erythrocytes and platelets) concentrations of Zn.
Methods:
Forty young men, divided into a training group (TG; n = 20; 18.15 ± 0.27 years; 68.59 ± 4.18 kg; 1.76 ± 0.04 m) and a control group (CG; n = 20; 19.25 ± 0.39 years; 73.45 ± 9.04 kg; 1.79 ± 0.06 m), participated in this study. The TG was formed by semiprofessional soccer players from a youth category with a regular training plan of 10 h/week. The CG was formed by healthy men who did not practice physical exercise and had not followed any specific training plan. Plasma, serum, urine, erythrocyte, and platelet samples of Zn were obtained and analyzed by inductively coupled plasma mass spectrometry.
Results:
The TG showed elevated plasma Zn concentrations (p < 0.01) despite similar intakes. However, TG showed reduced absolute (p < 0.01) and relative (p < 0.05) Zn concentrations in erythrocytes.
Conclusions:
Athletes who underwent regular physical training showed elevated plasma and reduced erythrocyte Zn concentrations despite similar intakes to the CG.
... Muscle tissue has the highest concentrations of Zn in the body, being associated with myogenesis, K + transport and depolarization of the membrane, uptake, and glucose and lactate dehydrogenase activity [67,68]. In athletes, an acute session of exercise causes increases in the plasma level of Zn, correlated with an increase in the level of catecholamines and intensity of exercise [69]. However, after the end of the exercise, both trained and untrained subjects present reduced Zn levels over a period of up to 24 h [23,67,70]. ...
The objective of the study was to evaluate the circulating levels of chemical elements after exercise-induced muscle damage (EIMD) followed by the repeated bout effect (RBE). Seven physically active subjects (26.5 ± 4.0 years) performed two sessions of EIMD (5 sets of 20 drop jumps), the second session 14 days after the first for RBE assessment. Blood collections, countermovement jump (CMJ), squat jump (SJ), and delayed-onset muscle soreness (DOMS) were performed before (Pre), after (Post), and 24, 48, and 72 h after the exercise session. Creatine kinase (CK) was detected by biochemical analysis and the concentration of chemical elements by total reflection X-ray fluorescence (TXRF). Differences between time points and sessions were assessed with two-way ANOVA and the effect size (ES). EIMD induced a reduction in the CMJ at 24 h (P < 0.05) and an increase in DOMS at 24 h (P < 0.01) and 48 h (P < 0.01), and CK at 72 h (P < 0.05). RBE alleviated all symptoms of EIMD in the second session (P > 0.05). EIMD induced a large to very large ES for Zn reduction at 24 h (− 1.37) and 72 h (− 0.93) and Br (− 0.83) at 72 h. RBE presented large to very large ES for the increase in P at 48 h (0.92); Cl at 24 h (1.04); K at 24 h (0.91), 48 h (1.10), and 72 h (0.96); Ca at 72 h (0.92); and Fe at 24 h (0.85). RBE influenced the concentration of elements associated with fatigue (K, Ca, Cl), inflammatory response, and glucose metabolism (Zn).
... Recent authors have reported contradictory results regarding the cortisol levels after 21 days of physical activity, even though the methodology was approximately the same. Only the duration of aerobic activity was different; thus, this may be one important factor for the contradictory results 15 . If we look at studies conducted in humans, there is evidence that participants with higher levels of aerobic fitness show lower levels of cortisol after physical and mental Figure 4: Comparison of cortisol levels among groups. ...
History • ABSTRACT Introduction: Physical inactivity has been identified as a major risk factor for global mortality, causing approximately 2 million deaths globally, whereas the physical activity of moderate intensity has significant benefits for health. Exposure to stress results in changes in the endocrine and autonomic nervous systems, as well as behavioral changes which allow an organism to adapt to environmental changes. This study aimed to assess changes in cortisol levels and body temperature in rats after forced swim tests. Methods: Female Wistar rats were divided into two groups: a control group (n = 10; not subjected to a forced swim test) and an experimental group (n = 10; subjected to a forced swim test). The forced swim test (60-90 min) was given to the experimental group for 21 days. Body temperature was measured rectally every day, and blood was taken from the animals on the 1 st , 7 th , 14 th , and 21 st days of the experiment to determine cortisol levels using a Mouse/Rat Cortisol ELISA protocol. Results: The results showed a statistically significant difference in the cortisol level between the groups on day 21 (p < 0.05). We found a significant reduction in the recurrent temperature after exposure to physical stress. Conclusions: Regular aerobic activity at a submaximal level for 21 days can reduce the hormonal stress response in female Wistar rats.
... Endurance training in athletes during long periods results in the mobilization of some TEs into the circulation [8]. Important interactions have been reported between TE concentrations and the antioxidant system, as TE influences antioxidant enzymes and vice versa [9,10]. Toxic TEs such as arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg) increase reactive oxygen species (ROS) production and can cause oxidative stress (OS) due to the imbalance between oxidants and antioxidants in favor of oxidants, which alters the correct functioning of thyroid hormones and the hypothalamic-pituitary-adrenal (HPA) axis [11]. ...
The aim of this study was to determine the possible correlations between essential and toxic trace elements of plasma with several anthropometric and body composition parameters and performance in endurance runners. Sixty-five high-level middle and long-distance runners (21 ± 3 years; 1.77 ± 0.05 m; 64.97 ± 7.36 kg; VO 2 max. 67.55 ± 4.11 mL/min/kg) participated in the present study. Abdominal, subscapular, iliac crest, triceps, front thigh and medial calf skinfold thicknesses and an incremental test until exhaustion were recorded. Body, fat, muscle and bone mass were estimated. Plasma trace elements were analyzed with inductively coupled plasma mass spectrometry (ICP-MS). Correlations and simple linear regression were used to assess the relationship between trace elements and several variables. Different skinfolds, fat mass, muscle mass and bone mass correlated positively and negatively with trace elements such as copper, manganese, selenium, vanadium, zinc, lithium, rubidium, strontium, arsenic, beryllium and lead. Lithium was related with performance. In conclusion, endurance training causes changes in the body concentrations of several trace elements that trigger modifications in body composition that may be interesting, if confirmed in the future, for the control of metabolic diseases such as obesity.
... Acute exercise is considered a stress condition, since it stimulates the hypothalamus-pituitary-adrenal (HPA) axis and induces metabolic and endocrine changes to maintain homeostasis under the new physiological conditions (Raastad et al., 2000;Leal-Cerro et al., 2003;Soria et al., 2015;Chen et al., 2017). The hypothalamic paraventricular nucleus (PVN) is at the beginning of the HPA axis and releases CRH and/or AVP neurochemical molecules during stress responses. ...
It has been demonstrated that physical activity contributes to a healthier life. However, there is a knowledge gap regarding the neural mechanisms producing these effects. One of the keystones to deal with this problem is to use training programs with equal loads of physical activity. However, irregular motor and stress responses have been found in murine exercise models. Habituation to forced exercise facilitates a complete response to a training program in all rodents, reaching the same load of physical activity among animals. Here, it was evaluated if glucose and lactate – which are stress biomarkers – are increased during the habituation to exercise. Sprague-Dawley rats received an 8-days habituation protocol with progressive increments of time and speed of running. Then, experimental and control (non-habituated) rats were subjected to an incremental test. Blood samples were obtained to determine plasmatic glucose and lactate levels before, immediately after and 30 min after each session of training. Crh and Avp mRNA expression was determined by two-step qPCR. Our results revealed that glucose and lactate levels are not increased during the habituation period and tend to decrease toward the end of the protocol. Also, Crh and Avp were not chronically activated by the habituation program. Lactate and glucose, determined after the incremental test, were higher in control rats without previous contact with the wheel, compared with habituated and wheel control rats. These results suggest that the implementation of an adaptive phase prior to forced exercise programs might avoid non-specific stress responses.
... If we can connect this with sedentary life of human people, this fact should be considered because according to the evidence there is high number of persons with high levels of stress conditions like anxiety, depression, mood disorders and they should be aware that their sedentary life can have side effects in their stress hormone levels (27,28) which can lead to several pathologies. Pain perception is another factor that has to be considered in people, many studies have been conducted about pain threshold. ...
Introduction: Physical activity is one important factor in the nervous system of animals, it may affect the structure also the function of the brain. Regular aerobic exercises have a good effect on the whole body and thus improves the sense of well-being. Aim: The aim of this ex-periment was to evaluate the effect of aerobic physical activity in white laboratory rats for 21 days. Methods: The experimental animals used were twenty Wistar rats, divided into 2 groups of 10 animals they were subjected to forced swim test for 21 days for 60-90 min swim. The evaluation of levels of Adrenaline was performed on 1st, 7th, 14th day and on the last day of the
experiment day 21 using ELISA kit protocol, also body mass was compared between groups. Results: Our results showed that inducing aerobic physical activity for 21 days on the rats affects their levels of adrenaline. Comparatively, the control group of rats had sinificantly higher levels of adrenalin compared with day 21 (p=0.435) but lower compared with day 7 and 14 (p=0.231). There was also a difference in body mass which demonstrates adaptability to the surroundings and better coping with physical stress. Conclusion: Regular aerobic activ-ity for 21 days, for 60-90 min swim has a positive impact on adrenaline level also this aerobic exercise protocol could have a positive impact on reducing and maintaining body weight, thus preventing overweight
... Another study have reported that after 4 w of moderate exercise, 45 min of treadmill running produced a significant positive increase in cortisol level (Alghadir, Gabr, & Aly, 2015). In addition, a single running test for 2 h increased cortisol levels (Viru, Hackeny, Valja, Karelson, Janson, & Viru, 2001;Jiang, Kawashima, Iwasaki, Uchida, Sugimoto, & Itoi, 2004;Okutsu, Suzuki, Ishijima, Peake, & Higuchi, 2008), similar to acute stress (Soria, Gonzalez-Haro, Anson, & Lopez-Colon, 2015). The above mentioned data showed that 2 h of aerobic physical activity for 7 d produced a significant increase in cortisol levels in Wistar rats. ...
Engaging in regular physical activity is one of the best ways to improve overall health. Physical activity can produce differences in neural and endocrine systems. However, it is challenging to promote regular physical activity in a population that is predominantly sedentary. Therefore, exercise protocols are used to rehabilitate patients with chronic musculoskeletal conditions, cardiorespiratory and mood disorders. The aim of this study was to observe differences in hormonal status after regular aerobic physical activity for 1-7 d. This in vivo experiment analyzes the impact of physical stress on the level of cortisol. A total of 20 Wistar rats were divided into 2 groups of 10 animals per group (i.e., the-control group, and the group of rats that was subjected to the forced swim test for 7 d. On the 1st and 7th day of the experiment, blood was taken from animals in order to determine the level of cortisol using the Mouse/Rat Cortisol ELISA protocol. Our results showed that by inducing physical stress for 1-7 d on the rats, their cortisol levels decreased. The results showed that regular aerobic activity for 7 d (i.e., 60-90 min of swimming) had a positive impact on lowering the levels of stress hormone cortisol.
... In this sense, a recent study found an increase of Se serum after exercise in well trained athletes. Nonethe less, the mentioned investigations did not correct the values for haemoconcentration (Soria et al., 2015). In heat stress, Wang et al. (2012) found a depletion of Se after intense basketball exercise, but did not correct for haemoconcentration, which is possibly why the values they obtained returned to baseline after 2 h. ...
Introduction: The effect of hyperthermia on the antioxidant system in the human organism is well known.
Aim: The objective of this study was to observe the effects of heat on the concentration of Se and Zn, elements related to antioxidant systems.
Methods: Twenty-nine subjects voluntarily participated in this study. They were divided into a control group (CG; n = 14) and an experimental group (EG; n = 15). All of them underwent two incremental tests until exhaustion in normothermia (22 °C, 20–40%RH) and hyperthermia (42 °C, 20–40%RH). EG experienced nine sessions of repeated heat exposure at high temperatures (100 °C, 20%RH) for three weeks (HEHT). After the intervention, the initial measurements were repeated. Urine and blood samples were collected before and after each test. Additionally, sweat samples were collected after tests in hyperthermia.
Results: There were no significant changes in serum. An increase in the elimination of Zn and Se in EG was ob- served in urine after HEHT (p < .05). The elimination of Zn by sweating decreased after HEHT in EG (p < .05). Conclusions: Exposure to heat at high temperatures increases the urinary excretion of Se and Zn.
... In turn, calcium launches a number of other signaling events (e.g., activates calmodulin-dependent kinases) [3]. In addition to calcium, other metals, such as magnesium, copper, and zinc are important, and their transportation to and from cells may vary, depending on the activity of adrenaline signaling [4,5]. The levels of these metals in cells are determining factors in the regulation of energy metabolism. ...
Up until now, changes in biochemical and physiological parameters occurring a long time after stress are not yet elucidated. This is particularly the case for metals, some of which may considerably influence other branches of metabolism, such as bioenergetics and antioxidant defense. The aim of the current study was to investigate changes in levels of minerals (calcium and magnesium) and trace elements (copper and zinc) in erythrocytes and the liver of rats injected once or twice (modeling repeated stress) with adrenaline. The tissues were sampled 0.5 and 24 hours after the injection. A single injection of adrenaline in rats led to a dramatic increase in the levels of zinc (Zn), magnesium (Mg), and calcium (Ca) in their erythrocytes and liver, without a return to the control level (unstressed animals) after 24 hours. The levels of copper (Cu) increased 0.5 hour after a single adrenaline injection in erythrocytes and the liver, but returned to the control level after 24 hours. Double injection of rats with adrenaline led to an increase in the levels of Cu and Zn in their erythrocytes, and Mg in the liver, without a return to the control level after 24 hours. On the other hand, the double injection led to a drastic but transient increase in levels of Mg and Ca in erythrocytes, and Cu, Zn, and Ca in the liver. Thus, injection with adrenaline results in dramatic changes in levels of minerals and trace elements, which do not return to the control level after stress. Low doses of adrenaline lead to more stable changes in levels of essential metals.
... Studies show changes in zinc homeostasis in athletes [8][9][10]. The systematic review and meta-analysis of Chu et al. [8], for example, indicated significant increase in serum zinc concentrations immediately after an aerobic exercise session, and they showed that changes in serum zinc are influenced by exercise intensity, the mode of exercise and the participants training status. ...
This study aimed to assess the relation between zinc status and inflammation biomarkers in adolescent judokas. This cross-sectional study included 52 male adolescents, aged between 14 and 19 years, who were subdivided into two groups: judoka group (n = 25) and control group (n = 27). Zinc intake was monitored using 3-day food records and the NutWin software version 1.5. The plasma and erythrocyte zinc concentrations were determined by flame atomic absorption spectrophotometry. Analysis of cytokines (IL-1β, IL-6, and TNF-α) was performed. The mean values of zinc concentration in the diet were found to be higher than those recommended (11.0±3.9 mg/day and 20.3±11.9 mg/day for control group and judokas, respectively) although there was no significant difference between the groups. The mean plasma concentrations of zinc were below the reference range (71.4±16.0 μg/dL and 71.9±13.8 μg/dL for control group and judokas, respectively), without a significant difference between the groups. The mean concentrations of zinc erythrocyte were within the reference range (41.2±8.6 μg/gHb and 42.6±11.3 μg/gHb for control group and judokas, respectively), without a significant difference between the groups. There was no significant difference in the inflammatory biomarkers between the judokas and controls. There was not a significant correlation between biochemical parameters of zinc and inflammation biomarkers in adolescent judokas. Regarding the data found in the study, it can be concluded that the athletes evaluated have low plasma zinc concentrations, normal erythrocyte values, and high dietary intake of zinc. Moreover, the study don't show a relationship between zinc parameters and inflammatory markers evaluated.
... Regardless of the supplement used, blood lactate concentration increased with the advancement of exercise duration, as occurred in other studies [35,36]. However, we did not find statistical differences among supplements used. ...
... In order to balance homeostasis, exercise results in physiological and psychological stresses by causing endocrinological changes during challenging coordinative movements. It triggers a coordinated series formed by physiological responses including the involvement of especially basic two stress activation systems such as hypothalamus-pituitaryadrenal axis and sympathetic nervous system (Soria et al. 2015, Furtado et al. 2016. Cortisol, which is considered as a stress hormone, is released when the body comes across with any kind of threat or danger and activates the sympathetic nervous system by mobilising energy sources. ...
Objective: This study aimed to examine the effect of CHO-E consumption after high-intensity exercise on insulin, cortisol hormones and blood glucose responses, which is important for performance and recovery in athletes.
Methods: Sixteen volunteers, male athletes, participated into this study. Athletes were divided into two groups as experiment (CHO-E) and placebo (PLA). Blood was taken from the athletes three times as basal, post-exercise (PE) and 2 h after ingestion of supplement (PS).
Results: When inter-group comparisons, insulin was significantly higher in the CHO-E group than the PLA group at the PS phase (p < .05). Cortisol significantly decreased in the CHO-E group at the PS compared to the PE (p < .05).
Conclusions: Carbohydrate–electrolyte consumption after high-intensity exercise, accelerates the recovery process by providing optimal recovery, and enable the metabolism to remain in the anabolic state by preventing it from entering in the catabolic process as well as provides hormonal balance in metabolism.
... A balanced nutrition reduces fatigue, increases the willingness and prevents the occurrence of injuries and infections, improving performance and recovery post-exercise [7,8]. Several clinical analysis, mainly in serum and urine, are performed regularly in athletes to check their physical condition, such as, oxygen intake, lactate, total protein, albumin, serum glucose, non-esterified fatty acids, thyroid hormones and insulin levels as well as plasma ions [9,10]. Recently an investigation involving the determination of element concentrations in the blood of long-distance runners revealed significant differences before and after training, as well as when compared with subjects not involved with physical activities [11]. ...
In this study Br, Ca, Cl, Fe, K, Mg, Na, S and Zn levels in blood samples of cyclists were investigated using neutron activation analysis technique. The results were compared to individuals of the same age and gender, but not involved with physical activities (control group), which showed considerable differences. A decrease mainly in Br (91 %) and Ca (78 %) and an increase in Fe (26 %), S (82 %) and Zn (22 %) levels were evidenced. These results emphasize the importance of blood monitoring for the maintenance of endurance athletes performance, particularly for Br, Ca and S.
... Therefore, heavy metals entering the human body via contact and ingestion have to be eliminated via the body's own mechanisms to maintain good health. Current studies have indicated that physical exercise can enhance the removal of trace elements from the human body; however, these studies mainly involved the essential trace elements, and the studies on heavy metals are rare and majorly focused on Cu and Zn (heavy metals that are beneficial to the human body) [26] [27]. In this study, we drew the conclusions from previous studies to further investigate the ability of sweat and urine to excrete heavy metals from the human body during physical exercise. ...
Bu çalışma, elit sporcularda kalsiyum, fosfor ve magnezyum seviyelerinin dikey sıçrama performansına etkisini araştırmayı amaçlamıştır. Araştırmaya 71 gönüllü sporcu (20 kadın, 51 erkek) katılmıştır. Katılımcıların ortalama yaşı 19,73±2,34’tür. Sporcuların kan örnekleri alınıp kalsiyum, magnezyum ve fosfor seviyeleri ölçülmüş, ardından dikey sıçrama testleri yapılmıştır. Katılımcıların bağımlı değişken sıçrama performansı ve bağımsız değişkenler kalsiyum, fosfor ve magnezyum üzerine etkisini belirlemek için basit regresyon analizi yapılmıştır. Yine aynı parametreler üzerinde ilişki aramak için Pearson Korelasyon analizi kullanılmıştır. Sonuçlar, sporcuların kalsiyum (9,52±0,36 mg/dL), magnezyum (2,06±0,15 mg/dL) ve fosfor (3,72±0,49 mg/dL) seviyelerinin dikey sıçrama performansı, güç, ortalama hız ve havada kalma süresi üzerinde anlamlı bir etkisinin olmadığını göstermiştir. Bu sonuçlar, sporcuların mineral seviyelerinin optimal düzeylerde olmasından kaynaklanabilir. Araştırma, elit sporcuların mineral seviyelerinin normal sınırlar içinde olduğunu ve bu seviyelerin performanslarını etkilemediğini ortaya koymuştur. Bu durum, sporcuların antrenman programlarının ve performanslarını geliştirmek için kullanılan stratejilerin tasarlanmasında dikkate alınması gereken önemli bir bilgidir. Araştırma, sporcuların performansını etkileyen birçok faktör olduğunu ve kalsiyum, magnezyum ve fosfor seviyelerinin sadece birkaç faktörden biri olduğunu vurgulamaktadır. Bu minerallerin optimal seviyede olması, sporcuların performanslarını artırmada yeterli olamayabilir. Bu nedenle, gelecekteki çalışmalarda farklı mineral seviyelerinde olan sporcuların performanslarının karşılaştırılması önerilmektedir.
Numerous functional measures related to anaerobic performance display daily variation. The diversity of tests and protocols used to assess anaerobic performance related to diurnal effects and the lack of a standardized approach have hindered agreement in the literature. Therefore, the aim of the present study was to investigate and systematically review the evidence relating to time-of-day differences in anaerobic performance measures. The entire content of PubMed (MEDLINE), Scopus, SPORTDiscus® (via EBSCOhost) and Web of Science and multiple electronic libraries were searched. Only experimental research studies conducted in male adult participants aged ≥ 18 yrs before May 2021 were included. Studies assessing tests related to anaerobic capacity or anaerobic power between a minimum of two time-points during the day (morning vs evening) were deemed eligible. The primary search revealed that a total of 55 out of 145 articles were considered eligible and subsequently included. Thirty-nine studies assessed anaerobic power and twenty-five anaerobic capacity using different modes of exercise and test protocols. Forty-eight studies found several of their performance variables to display time-of-day effects, with higher values in the evening than the morning, while seven studies did not find any time-of-day significance in any variables which were assessed. The magnitude of difference is dependent on the modality and the exercise protocol used. Performance measures for anaerobic power found jump tests displayed 2.7 to 12.3% differences, force velocity tests ~8% differences, sprint tests 2.7 to 11.3% differences and 5-m multiple shuttle run tests 3.7 to 13.1% differences in favour of the evening. Performance measures for anaerobic capacity found Wingate test to display 1.8 to 11.7% differences and repeated sprint tests to display 3.4 to 10.2% differences. The only test not to display time-of-day differences was the running based anaerobic sprint test (RAST). Time-of-day variations in anaerobic performance has previously been partially explained by higher core-body and/or muscle temperature and better muscle contractile properties in the afternoon, although recent findings suggest that differences in methodology, motivation/arousal, habitual training times and chronotypes could provide additional explanations. There is a clear demand for a rigorous, standardised approach to be adopted by future investigations which control factors that specifically relate to investigations of time-of-day.
Background A factor favoring the swimming performance increase is the adaptation and readaptation of body energetic and functional systems to the physical and mental stress stimuli in training and competitions. The efficiency of monitoring the young swimmers’ training is based on a precise determination of the changes in the specific adaptations. The evaluation and control of the biochemical, mental and motor changes ensure the knowledge of the particularities of body adaptation in different training stages. Methods Six young swimmers aged 12–16 years specialized in 100 m event participated in this study, conducted in four stages (E1–general, E2–specific, E3–pre-competitive and E4–competitive). The distress occurrence during adaptation to training and competition stimuli was studied in 3 levels: mental (Cohen & Williamson Test (CWT), Cohen Perceived Stress Test (CPST), Competition Anxiety Test (SCAT), Crăciun Test (CT)), motor (workouts monitoring, planning of means on training areas, anaerobic threshold assessment and average training speed calculation) and biochemical (blood lactate (La) and blood glucose (Glu) before and after effort—5 and 15 minutes; level of metabolic biochemical parameters, lymphocytes and blood glucose, and also hormonal parameters—norepinephrine, prolactin and cortisol—before and after competition effort). Results Quantity results of the mental, motor and biochemical tests were analyzed in groups; the quality results for each subject in dynamics were analyzed by comparison and correlation. Psychological tests showed increases in athletes’ mental behavior by 34% at CWT (p
Purpose: This study was aimed to assess selenium and zinc status in female collegiate athletes and their relationship with dietary intake. Methods: Female collegiate athletic groups of judo and aerobics, and healthy sedentary collegiate females were recruited for this study and their serum selenium and zinc contents were measured by the neutron activation analysis (NAA) method. In addition, the dietary intake of subjects was measured using the two days 24-hour recall method. Results: Serum selenium in judo athletes was 10.7 µg/dl, which was significantly lower than that of aerobic athletes (12.2 µg/dl), but not different from that of the sedentary group (11.4 µg/dl). Additionally, serum zinc levels were 96.1 µg/dl and 90.2 µg/dl in aerobic and judo athletes, respectively, which did not differ significantly. Moreover, dietary selenium and zinc intake of the athletic groups did not differ significantly from that of the sedentary female group. Overall, 33.3% of the serum selenium concentration variation was explained by the intake of vitamin E, selenium and saturated fatty acids, while 14.7% of the serum zinc level variation was explained by the intake of saturated fatty acids. The strongest dietary indicator for serum selenium and zinc levels was saturated fatty acids intake. Conclusion: Judo athletes appear to have lower selenium status than aerobic athletes, suggesting different body selenium status according to sport type. To maintain body selenium and zinc levels, the dietary intake of saturated fatty acids should be decreased.
BACKGROUND: Exercise brings about endocrinological changes to balance homeostasis during challenging coor-dinative movements, thus leading to physiological and psychological stress. The present study aimed to assess, by non-invasive means, the stress levels and cortisol awakening responses (CAR) of athletes playing a football match. METHODS: Male football (soccer) players (N.=14, age 21.3±3.25 years) in a regional professional league took part in the study. To determine cortisol responses, saliva samples were taken on 3 different days during a regular league match. The salivary cortisol levels of the athletes were analyzed by ELISA. All participants were asked to fill in STAI-T questionnaires. The repeated measures test was used for cortisol comparisons between the sampling times and for CAR comparisons between days. RESULTS: According to the analyses, CAR levels decreased on the game day and increased the day after. As the competition time approached, the values beginned to rise but returned to initial values half time. At the end of the match, a slight increase was observed. There were no statistically significant differences in CAR and competition samples. There were no correlations between cortisol parameters and STAI-T scores (P>0.05). CONCLUSIONS: Football is a team sport requiring coordinated team effort and this appeared to incluence current data. Moreover, significant hormonal fluctuations related to competition revealed that professional football players are well adapted to the competition releated stress.
Excessive metal exposure has been recognized as one of the detrimental factors for brain damage. However, the potential adverse effects induced by heavy metals on monoamine neurotransmitter pathways remains poorly understood. Our study aimed to investigate the possible association between metal exposure and neurotransmitter metabolism. By a cross-sectional investigation, 224 electroplating workers and 213 non-electroplating exposure workers were recruited in the exposure and control groups. Metal exposure levels were analyzed using inductively-coupled plasma mass spectrometry and monoamine neurotransmitter pathway metabolites were measured by ultra-performance liquid chromatography tandem mass spectrometry in human urine samples. Multivariate linear regression model was used to assess the dose-response relationships of urinary metals and neurotransmitter pathway metabolites. Significant dose-dependent trends of urinary vanadium quartiles with all metabolites were observed, and the trends demonstrated significance after multiple testing correction. It also showed that urinary chromium levels were significantly associated with decreased serotonin level and cadmium was positively associated with norepinephrine and epinephrine. In addition, arsenic was positively associated with tryptophan, serotonin dopamine and norepinephrine. Iron was positively associated with increased homovanillic acid (HVA) and epinephrine while nickel was negatively associated with increased epinephrine levels. Zinc was positively related to tryptophan, kynurenin (KYN), 5-hydroxyindole acetic acid (5-HIAA), dopamine, HVA and norepinephrine. There was no significant association between urinary copper with any other metabolites after adjusting of multiple metal models. Metal exposure may be associated with neurotransmitter metabolism disturbances. The present work is expected to provide some support in the prevention and management of metal-associated neurological diseases.
Active physical exercises and growth are associated with mineral imbalances in young athletes. The purpose of this study was to examine the impact of sport-related factors on tissue mineral status in adolescent female athletes. Saliva and hair samples were used for the analysis of immediate and more permanent tissue mineral status, respectively. Samples taken from a control non-athletic female group and two groups of female athletes (field hockey and fencing) were analyzed for seven essential minerals: calcium, chromium, iron, potassium, magnesium, selenium and zinc. Inductively-coupled plasma mass spectrometry was used for the quantification of elements having very low concentration range in samples (Se, Cr and Zn) whereas inductively coupled plasma optical emission spectrometry was used for quantification of more ubiquitous elements (Mg, К, Са, Fe). The obtained results for athletic groups were compared with control. Female athletes had increased levels of selenium in both saliva and hair as well as chromium in saliva. Field hockey players had the higher level of zinc in hair whereas fencers had the lower levels of salivary calcium. Strong negative correlation between potassium levels in saliva and hair was identified. Iron and magnesium did not differ between the studied groups. In conclusion, novel sport-specific features of chromium tissue levels in female athletes were found. The studied sport disciplines have different impact on the distribution of osteoporosis-related minerals (calcium and zinc). Our finding can help in the development of osteoporosis preventive trainings and in the proper nutrient supplementation to correct mineral imbalances in female athletes.
This study examined the influence of exercise intensity upon the cortisol response of the hypothalamic-pituitaryadrenal (HPA) axis. Specifically, we examined exercise at intensities of 40, 60, and 80% maximal oxygen uptake (VO2max) in an attempt to determine the intensity necessary to provoke an increase in circulating cortisol. Twelve active moderately trained men performed 30 min of exercise at intensities of 40, 60, and 80% of their VO2max, as well as a 30-min resting-control session involving no exercise on separate days. Confounding factors such as time of day — circadian rhythms, prior diet — activity patterns, psychological stress, and levels of exercise training were controlled. Cortisol and ACTH were assessed in blood collected immediately before (pre-) and after (post-) each experimental session. Statistical analysis involved repeated measures analysis of variance and Tukey posthoc testing. The percent change in cortisol from pre- to post-sampling at each session was: resting-control, 40, 60, and 80% sessions (mean±SD) =−6.6±3.5%, +5.7±11.0%, +39.9±11.8%, and +83.1±18.5%, respectively. The 60% and 80% intensity magnitude of change was significantly greater than in the other sessions, as well as from one to another. The ACTH responses mirrored those of cortisol, but only the 80% exercise provoked a significant (pACTH). In contrast, low intensity exercise (40%) does not result in significant increases in cortisol levels, but, once corrections for plasma volume reduction occurred and circadian factors were examined, low intensity exercise actually resulted in a reduction in circulating cortisol levels.
Selenium is an essential trace element in the diet of mammals which is important for many physiological functions. However, a number of epidemiological studies have suggested that high selenium status is a possible risk factor for the development of type 2 diabetes, although they cannot distinguish between cause and effect. Selenoprotein P (Sepp1) is central to selenium homeostasis and widely expressed in the organism. Here we review the interaction between Sepp1 and glucose metabolism with an emphasis on experimental evidence. In models with or without gene modification, glucose and insulin can regulate Sepp1 expression in the pancreas and liver, and vice versa. Especially in the liver, Sepp1 is regulated virtually like a gluconeogenic enzyme. Combining these data suggests that there could be a feedback regulation between hepatic Sepp1 and pancreatic insulin and that increasing circulating Sepp1 might be the result rather than the cause of abnormal glucose metabolism. Future studies specifically designed to overexpress Sepp1 are needed in order to provide a more robust link between Sepp1 and type 2 diabetes.
Selenium (Se) is an essential trace element used for biosynthesis of selenoproteins and is acquired either through diet or cellular recycling mechanisms. Selenocysteine lyase (Scly) is the enzyme that supplies Se for selenoprotein biosynthesis via decomposition of the amino acid selenocysteine (Sec). Knockout (KO) of Scly in a mouse affected hepatic glucose and lipid homeostasis. Mice lacking Scly and raised on an Se-adequate diet exhibit hyperinsulinemia, hyperleptinemia, glucose intolerance, and hepatic steatosis, with increased hepatic oxidative stress, but maintain selenoprotein levels and circulating Se status. Insulin challenge of Scly KO mice results in attenuated Akt phosphorylation but does not decrease phosphorylation levels of AMP kinase alpha (AMPKα). Upon dietary Se restriction, Scly KO animals develop several characteristics of metabolic syndrome, such as obesity, fatty liver, and hypercholesterolemia, with aggravated hyperleptinemia, hyperinsulinemia, and glucose intolerance. Hepatic glutathione peroxidase 1 (GPx1) and selenoprotein S (SelS) production and circulating selenoprotein P (Sepp1) levels are significantly diminished. Scly disruption increases the levels of insulin-signaling inhibitor PTP1B. Our results suggest a dependence of glucose and lipid homeostasis on Scly activity. These findings connect Se and energy metabolism and demonstrate for the first time a unique physiological role of Scly in an animal model.
Zinc and selenium are essential minerals and have roles for more than 300 metabolic reactions in the body. The purpose of this study was to investigate how exhaustive exercise affects testosterone levels and plasma lactate in cyclists who were supplemented with oral zinc and selenium for 4 weeks. For this reason, 32 male road cyclists were selected equally to four groups: PL group, placebo; Zn group, zinc supplement (30 mg/day); Se group, selenium supplement (200 μg/day); and Zn-Se group, zinc-selenium supplement. After treatment, free, total testosterone, and lactate levels of subjects were determined before and after exhaustive exercise. Resting total, free testosterone, and lactate levels did not differ significantly between groups, and were increased by exercise (P > 0.05). Serum total testosterone levels in Zn group were higher than in Se group after exercise (P < 0.05). Serum-free testosterone levels in the Zn group were higher than the other groups (P < 0.05).There was an insignificant difference between levels of lactate in the four groups after exercise (P > 0.05). The results showed that 4-week simultaneous and separately zinc and selenium supplementation had no significant effect on resting testosterone and lactate levels of subjects who consume a zinc and selenium sufficient diet. It might be possible that the effect of zinc supplementation on free testosterone depends on exercise.
The present study aims to examine the effect of supplementation of zinc on the distribution of various elements in the sera of diabetic rats subjected to an acute swimming exercise. A total of 80 Sprague-Dawley-type adult male rats were equally allocated to one of eight groups: Group 1, general; Group 2, zinc-supplemented; Group 3, zinc-supplemented diabetic; Group 4, swimming control; Group 5, zinc-supplemented swimming; Group 6, zinc-supplemented diabetic swimming; Group 7, diabetic swimming; and Group 8, diabetes. The rats were injected with 40 mg/kg/day subcutaneous streptozotocin (STZ) twice, with a 24-h interval between two injections. Zinc was supplemented at a dose of 6 mg/kg/day (ip) for 4 weeks. Blood samples were collected at the end of the 4-week study, and serum levels of lead, cobalt, molybdenum, chrome, sulfur, magnesium, manganese, sodium, potassium, phosphorus, copper, iron, calcium, zinc, and selenium (mg/L) were determined with atomic emission. The lowest molybdenum, chrome, copper, iron, potassium, magnesium, sodium, phosphorus, lead, selenium, and zinc values were obtained in Group 7 and 8. These same parameters were higher in the swimming exercise group (Group 4), relative to all other groups. The values in zinc-supplemented groups were found lower than the values in Group 4, but higher than those in Group 6 and 7. The results obtained from the study demonstrate that acute swimming exercise and diabetes affect the distribution of various elements in the serum, while zinc supplementation can prevent the negative conditions associated with both exercise and diabetes.
Exercise is a paradigm of a stress situation. The adaptive response to stressors comprises the activation of the hypothalamic-pituitary-adrenal (HPA) axis and components of the autonomic sympathetic system. An aseptic inflammatory reaction is triggered by exercise, involving the stimulation of the so-called proinflammatory cytokines, such as tumor necrosis factor α (TNFα), interleukin-1 (IL-1), and IL-6. The anti-inflammatory cytokines IL-2, IL-8, and IL-10 increase moderately during resistance exercise. To investigate the effect of a short bout of resistance exercise on components of the stress and inflammatory responses during the exercise period, 17 healthy, young, untrained male volunteers were studied during 3 equal consecutive cycles of resistance exercises of 30 min total duration. Blood sampling was performed at baseline and at the end of each cycle. Lactate, cortisol, catecholamines (epinephrine, norepinephrine), IL-1α, IL-1β, IL-2, IL-6, IL-8, IL-10, epidermal growth factor (EGF), and monocyte chemotactic protein-1 (MCP-1) were measured at all time-points. Circulating levels of catecholamines and lactate increased significantly (P < 0.05) whereas cortisol did not. During the time course of the exercise, circulating levels of TNFα, IL-2, and EGF increased, whereas MCP-1 decreased significantly. IL-1α, IL-1β, IL-6, IL-8, and IL-10 levels did not change significantly. Statistically significant positive linear correlations were found between areas under the curve for increases in levels of IL-2 and TNFα, TNFα and cortisol, as well as epinephrine and norepinephrine. We conclude that acute resistance exercise results in catecholaminergic, but not HPA axis stimulation during exercise, in parallel with a mild inflammatory reaction. The absence of a major inflammatory reaction and of a cortisol increase during acute resistance exercise makes this a good candidate for the exercise of sedentary individuals.
The purposes of this study were to examine the effect of acute incremental exercise on the performance of a central executive task; the responses of the sympathoadrenal system (SAS) and hypothalamic-pituitary-adrenal axis (HPAA) during exercise, while simultaneously carrying out the central executive task; and the ability of Delta plasma concentrations of epinephrine, norepinephrine, adrenocorticotropin hormone (ACTH) and cortisol to predict Delta performance on the central executive task. Subjects undertook a flanker task at rest and during exercise at 50% and 80% maximum aerobic power (MAP). SAS and HPAA activity were measured pre- and post-treatment by plasma concentrations of catecholamines, and cortisol and ACTH, respectively. Reaction time (RT) and number of errors for congruent and incongruent trials on the flanker task showed significant main effects with performance at 80% MAP higher than in the other conditions. RT post-correct responses were significantly faster than RT post-error at rest and 50% MAP but not at 80%. Pre- and post-treatment catecholamines showed a main effect of exercise with a linear increase. Post-treatment ACTH concentrations at 80% MAP were significantly greater than in the other conditions. Delta epinephrine and ACTH combined were significant predictors of Delta RT and Delta norepinephrine was a significant predictor of Delta number of errors. It was concluded that exercise must be at a high intensity to affect performance on the flanker task. Both the SAS and HPAA appear to play a role in the exercise-cognition interaction.
Zinc is an essential micronutrient for human health and has numerous structural and biochemical roles. The search for a reliable, sensitive, and specific index of zinc status has been the subject of considerable research, which has resulted in the identification of a number of potentially useful biomarkers.
The objective was to assess the usefulness of biomarkers of zinc status in humans.
The methods included a structured search strategy using Ovid MEDLINE, EMBASE (Ovid), and the Cochrane Library CENTRAL databases; formal inclusion and exclusion criteria; data extraction into an Access database; quality and validity assessment; and meta-analysis.
Data on 32 potential biomarkers from 46 publications were analyzed. Plasma zinc concentration responded in a dose-dependent manner to dietary manipulation in adults, women, men, pregnant and lactating women, the elderly, and those at low and moderate baseline zinc status. Urinary zinc excretion responded to zinc status overall and in all subgroups for which there were sufficient data. Hair zinc concentration also responded, but there were insufficient studies for subgroup analysis. Platelet, polymorphonuclear cell, mononuclear cell, and erythrocyte zinc concentration and alkaline phosphatase activity did not appear to be effective biomarkers of zinc status.
This systematic review confirms that in healthy individuals, plasma, urinary, and hair zinc are reliable biomarkers of zinc status. Further high-quality studies using these biomarkers are required, particularly in infants, adolescents, and immigrant population groups for whom there are limited data. Studies are also required to fully assess a range of additional potential zinc biomarkers.
To understand the effect of selenium intake on health, it is important to identify sensitive and population-specific biomarkers of selenium status.
The objective of this systematic review was to assess the usefulness of biomarkers of selenium status in humans.
The methods included a structured search strategy on Ovid MEDLINE, EMBASE (Ovid), and Cochrane databases; formal inclusion and exclusion criteria; data extraction into an Access database; validity assessment; and meta-analysis.
The data from 18 selenium supplementation studies (of which 9 were randomized controlled trials and 1 was considered to be at low risk of bias) indicate that plasma, erythrocyte, and whole-blood selenium, plasma selenoprotein P, and plasma, platelet, and whole-blood glutathione peroxidase activity respond to changes in selenium intake. Although there is a substantial body of data for plasma selenium, more large, high-quality, randomized controlled trials are needed for this biomarker, as well as for the other biomarkers, to explore the reasons for heterogeneity in response to selenium supplementation. There was insufficient evidence to assess the usefulness of other potential biomarkers of selenium status, including urinary selenium, plasma triiodothyroxine:thyroxine ratio, plasma thyroxine, plasma total homocysteine, hair and toenail selenium, erythrocyte, and muscle glutathione peroxidase activity.
For all potentially useful biomarkers, more information is needed to evaluate their strengths and limitations in different population groups, including the effects of varying intakes, the duration of intervention, baseline selenium status, and possible confounding effects of genotype.
The trace element selenium is an essential micronutrient for human health and its low levels in serum are implicated in the pathogenesis of several chronic diseases. Therefore, the determination of total selenium in serum may contribute to the assessment of the health and nutritional status of certain populations. The objective of the present work was to determine total selenium in the serum of 506 healthy volunteers that participated in the ATTICA study. Selenium was determined in serum by using the technique of inductively coupled plasma mass spectrometry. The mean serum selenium concentration was determined to be 91.8 +/- 33.7 microg/L (N = 506); 87.6% of women and 88.5% of men had serum selenium concentration below 125 microg/L, the cutoff considered to be required for optimal glutathione peroxidase activity. No association was found between serum selenium levels and the gender of the participants while a significant decline of selenium with age (p < 0.0001) was observed. According to our results, no anthropometric, lifestyle, nutritional, or biochemical indices were able to affect the association between serum selenium and age. This result may indicate that other factors such as selenium distribution as well as retention may be affecting the relationship between serum selenium and age.
Concentrations of 27 commonly estimated serum constituents were measured in blood sampled from 20 apparently healthy volunteers at 0830, 1230, and 1630 hours on each of four days, at weekly intervals. Time-dependent statistically significant (p less than or equal to 0.01) variation was observed in 12 of the constituents. The 15 constituents that showed no statistically significant diurnal variation included the immunoglobulins, other specific proteins, enzymes, cholesterol, calcium, copper, and magnesium. On the different days of the study consistent temporal patterns were observed in urea, creatinine, phosphate, zinc, bilirubin, triglyceride, total protein, and albumin. The magnitude of variation was particularly great in potassium, iron, zinc, and bilirubin. In general, day-to-day changes in concentration exceeded within-day changes, except for potassium, phosphate, and zinc, for which greater changes could be observed within-day than from one day to another at the same time.
Exercise of appropriate intensity is a potent stimulus for GH and cortisol secretion. Circadian and diurnal rhythms may modulate the GH and cortisol responses to exercise, but nutrition, sleep, prior exercise patterns, and body composition are potentially confounding factors. To determine the influence of the time of day on the GH and cortisol response to acute exercise, we studied 10 moderately trained young men (24.1 +/- 1.1 yr old; maximal oxygen consumption, 47.9 +/- 1.4 mL/kg.min; percent body fat, 13.2 +/- 0.6%). After a supervised night of sleep and a standard meal 12 h before exercise, subjects exercised at a constant velocity (to elicit an initial blood lactate concentration of approximately 2.5 mmol/L) on a treadmill for 30 min on 3 separate occasions, starting at 0700, 1900, and 2400 h. Blood samples were obtained at 5-min intervals for 1 h before and 5 h after the start of exercise; subjects were not allowed to sleep during this period. Subjects were also studied on 3 control days under identical conditions without exercise. There were no significant differences with time of day in the mean blood lactate and submaximal oxygen consumption values during exercise. The differences over time in serum GH and cortisol concentrations between the exercise day and the control day were determined with 95% confidence limits for each time of day. Exercise stimulated a significant increase in serum GH concentrations over control day values for approximately 105--145 min (P < 0.05) with no significant difference in the magnitude of this response by time of day. The increase in serum GH concentrations with exercise was followed by a transient suppression of GH release (for approximately 55--90 min; P < 0.05) after exercise at 0700 and 1900 h, but not at 2400 h. Although the duration of the increase in serum cortisol concentrations after exercise was similar (approximately 150--155 min; P < 0.05) at 0700, 1900, and 2400 h, the magnitude of this increase over control day levels was greatest at 2400 h. This difference was significant for approximately 130 min and approximately 40 min compared to exercise at 1900 and 0700 h, respectively (P < 0.05). The cortisol response to exercise at 0700 h was significantly greater than that at 1900 h for about 55 min (P < 0.05). A rebound suppression of cortisol release for about 50 min (P < 0.05) was observed after exercise at 2400 h, but not 0700 or 1900 h. Both baseline (before exercise) and peak cortisol concentrations were significantly higher at 0700 h than at 1900 or 2400 h (P < 0.01). We conclude that time of day does not alter the GH response to exercise; however, the exercise-induced cortisol response is modulated by time of day.
This review concerns various minerals (sodium, potassium, calcium, magnesium, phosphorus), trace elements (zinc, manganese, selenium, copper, iron, cobalt, iodine, chromium, fluorine, lead, cadmium) and other biological variables (nitric oxide, L-carnitine, glutamine, serum transferrin receptor, biopyrrins) in relation to hemorheologic effects, stress, immune response and infections during physical and sports activities. In athletes, macroelements in the ionized form contribute to heart and muscle contractions, oxidative phosphorylation and the synthesis and activation of enzymatic systems. Zinc (Zn) protects against the effects of increased free reactive oxygen species such as copper (Cu) and manganese (Mn) (Cu-Zn superoxide dismutases; Mn superoxide dismutase). Selenium in glutathione peroxidase protects the cardiovascular system and the muscles, and helps combat allergic and inflammatory diseases. Copper and iron are involved in many aspects of energy metabolism and are important components in the synthesis of hemoglobin, myoglobin and cytochromes. Fluorine and Cu protect the ligaments and tendons. Physical activity appears to be beneficial to urban residents who are exposed to metal pollution (lead, cadmium). The data cited in this review are often contradictory and incomplete. It is still unclear in many cases how minerals are involved in physiological changes, and much work remains.
This study examined the possibility that fatigue may modify the hormone responses to exercise. A group of 12 endurance trained athletes ran for 2 h (blood lactate concentrations of approximately 2 mmol x l(-1)) in order to induce fatigue. The subjects exercised for 10 min at 70% maximal oxygen uptake before (1st test) and after (2nd test) the 2 h run to assess hormone responsiveness. A 1 min anaerobic power test was performed to assess muscle power. Cortisol, growth hormone, testosterone and insulin concentrations were determined before and after the 1st and 2nd tests. The 1st test resulted in increases in concentrations (P < 0.05) of cortisol and growth hormone, a decrease in insulin concentration (P<0.01) and no change in testosterone concentration. The 2 h run caused decreases of insulin, increases of growth hormone concentration and variable responses in the concentrations of cortisol and testosterone. The 2nd test decreased insulin concentration further (P < 0.05), but responses of the concentrations of testosterone, growth hormone and cortisol were variable. In 6 subjects (group A) cortisol displayed an increase [mean (SD)] from baseline concentrations [+ 304.0 (60.0) nmol x l(-1)], while in the other 6 subjects (group B) a decrease or no change was seen [+ 3.1 (5.3) nmol x l(-1), between groups, P<0.05]. Growth hormone concentration was substantially higher in group A [+ 14.7 (4.8) ng x ml(-1)] than group B [+ 6.0 (2.9) ng x ml(-1)] following the 2nd test. In group A anaerobic muscle power was higher, while in group B it was lower, after the 2 h run than before the 2 h run (P < 0.05). The findings suggest that fatigue from prolonged endurance activity may introduce a resetting in the pituitary-adrenocortical component of the endocrine system, expressed either by intensified or by suppressed endocrine functions.
Exercise represents a physical stress that challenges homeostasis. In response to this stressor, the autonomic nervous system and hypothalamus-pituitary-adrenal axis are known to react and participate in the maintenance of homeostasis and the development of physical fitness. This includes elevation of cortisol and catecholamines in plasma. However, physical conditioning is associated with a reduction in pituitary-adrenal activation in response to exercise. On the other hand, highly trained athletes exhibit chronic mild hypercortisolism at baseline that may be an adaptive change to chronic exercise. In addition the proinflammatory cytokine, IL-6 is also activated, probably via catecholamines. On the other hand, the stress of chronic exercise induces certain changes to the thyroid axis. Peripheral thyroid hormone metabolism suppression is observed, and the result is a hormonal status similar to that of euthyroid sick syndrome (ESS), with suppression of T3 and elevation of rT3 plasma levels. One mechanism proposed involves exercise-activated pathways participating in the pathogenesis of ESS. This is realized through norepinephrine's activation of NF-kappaB. Neuroendocrine response to exercise stress involves activation of NF-kappaB resulting in inactivation of T3-dependent 5'-deiodinase gene expression and enzyme activity. Thus, ESS is generated in the periphery. On the other hand, activation and nuclear translocation of NF-kappaB leads to increased transcription of proinflammatory genes responsible for the expression of proinflammatory cytokines such as TNF-alpha and IL-6. These cytokines could activate cortisol, which in turn inhibits NF-kappaB activation through IkappaB and finally shuts down this cycle.
Introduction: The purpose of this study was to investigate how exhaustion exercise affects testosterone levels and plasma lactates in road cyclists supplemented with oral zinc and selenium for 4 weeks. Materials and Methods: Twenty-four male road cyclists volunteers, were selected from the Tehran Traffic team, and based on BMI were divided into three groups; the selenium, zinc, and controls. The status of zinc and selenium in subjects was assessed at baseline. After 4 weeks of supplementation free, total testosterone, and lactate levels of all subjects were determined before and after exercise. Data was analyzed according to repeated measures ANOVA, and the Bonfferoni post hoc test, with a significance level of P<0.05. Results: Resting total, free testosterone, and lactate levels did not differ significantly between groups, and were increased by exercise (P>0.05). Total testosterone levels in the Zn group were higher than in the Se group after exercise (P<0.05). Free testosterone levels in the Zn group were higher than the other groups (P<0.05). There was an insignificant difference between levels of lactate in the three groups after exercise (P>0.05). Conclusion: According to this study, 4-week selenium and zinc supplementation had no significant effect on testosterone or lactate levels of subjects who had a zinc and selenium sufficient diet. Zinc supplementation increased levels of total testosterone in contrast with selenium group, and also increased free testosterone versus the other groups, whereas there was no change in the levels of lactate in the three groups post-test.
Blood samples from 77 asymptomatic male runners were analyzed for serum zinc and copper. Whereas copper levels were within normal limits, the mean zinc level was 20% below control values and published norms. This study raises the question of whether runners are disposed to marginal zinc deficiency. If so, perhaps concern for the prevalence of zinc deficiency in the American diet should also be directed to the special diets of endurance runners.
Using inductively coupled plasma-mass spectrometry after samples microwave-assisted acid digestion, zinc (Zn), copper (Cu), and manganese (Mn) levels were measured in 14 different areas of the human brain of adult individuals (n = 42; 71 ± 12, range 50-101 years old) without a known history of neurodegenerative, neurological, or psychiatric disorder. The main goals of the work were to establish the "normal" (reference) values for those elements in the human brain and to evaluate the age-related changes, a prior and indispensable step in order to enlighten the role of trace element (TE) in human brain physiology and their involvement in aging and neurodegenerative processes. Considering the mean values for the 14 regions, Zn (mean ± sd; range 53 ± 5; 43-61 μg/g) was found at higher levels, followed by Cu (22 ± 5; 10-37 μg/g) and Mn (1.3 ± 0.3; 0.5-2.7 μg/g). The TE distribution across the brain tissue showed to be quite heterogeneous: the highest levels of Zn were found in the hippocampus (70 ± 10; 49-95 μg/g) and superior temporal gyrus (68 ± 10; 44-88 μg/g) and the lowest in the pons (33 ± 8; 19-51 μg/g); the highest levels of Cu and Mn were found in the putamen (36 ± 13; 21-76 μg/g and 2.5 ± 0.8; 0.7-4.5 μg/g, respectively) and the lowest in the medulla (11 ± 6; 2-30 μg/g and 0.8 ± 0.3; 0.2-1.8 μg/g, respectively). A tendency for an age-related increase in Zn and Mn levels was observed in most brain regions while Cu levels showed to be negatively correlated with age.
Nine male runners (23-46 yr) ran 6 mi near their maximal pace. Blood and urine samples were obtained prior to, immediately after, and 2 h following the run; 24-h urine collections were also taken on the run and nonrun days. Serum chromium increased significantly (P < 0.05) from 0.12 ± 0.02 (mean ± SE) to 0.17 ± 0.03 ng/mL immediately following running and remained elevated, 0.19 ± 0.03 ng/mL, after 2 h. Urinary chromium concentration was elevated several-fold 2 h following running and daily urinary chromium losses were about twofold higher on the day of the run compared to a rest day. Serum zinc was not significantly different from prerun values immediately following running, 81 ± 4 and 85 ± 4 pμg/dL, respectively, but then decreased significantly to 75 ± 4 2 h after exercise. Urinary zinc concentration was elevated more than twofold 2 h after running and total urinary losses on the day of the run were more than 1.5-fold higher than those on the nonrun day. Serum copper was not altered by exercise. Serum high density lipoprotein (HDL) cholesterol, but not total cholesterol increased significantly following running. HDL cholesterol values were similar to prerun values within 2 h of running. Serum triglycerides, phosphate, creatinine, bilirubin, uric acid, and alkaline phosphatase were also elevated immediately following running, whereas albumin, total protein, and blood urea nitrogen remained constant. These data demonstrate that accompanying the transitory changes in selected clinical indices caused by strenuous running there are alterations in chromium and zinc concentrations in serum and urine and increased specific urinary losses of these essential nutrients.
Changes in zinc (Zn) availability in muscle tissue that influence muscle performance in vitro have been observed. The effect of exercise of plasma Zn levels and urinary excretion of Zn was observed in sever untrained volunteers following brief intensive exercise and in seven trained volunteers after more prolonged road-running exercise. With brief exercise, plasma Zn decreased predominantly in the more loosely bound albumin fraction. Prolonged exercise resulted in a greater plasma Zn decrease of 30%. Urinary Zn excretion increased transiently with minimal effect on daily losses. However, weight loss by sweating was significant, and sweat Zn losses were greater than those in the urine. Exercise resulted in changes in Zn metabolism that may influence performance.
In humans, long-term exposure to uncontrollable and unpredictable life stressors is a major precipitant in the development of depressive disorders. There are strong evidences that depression is accompanied by lower serum zinc. The aim of present study is to assess the effects of repeated psychological stress (PS) on the zinc metabolism in rat. The rats were divided into control group and PS group which were subdivided into three subgroups: 7-day group, 14-day group, and recovery group (ten rats in each subgroup). PS model was created by a communication box which contains room A and room B. Rats in room A were only exposed to the responses of rats which were randomly given electrical shock for 30 min in room B. PS was given to rats for 30 min every morning for 14 days. The serum corticosterone (CORT), zinc in serum and tissues, and zinc apparent absorption after PS exposure were investigated. The results showed that the serum CORT increased and serum zinc decreased after 7 and 14 days of PS treatment. The zinc concentration in the liver was increased by 14 days PS exposure, whereas its concentration in the hippocampus was decreased by 7 and 14 days of PS exposure. There were no significant changes in zinc concentration in the heart, spleen, kidney, duodenum, cortex, and cerebellum. A decrease in the zinc apparent absorption was observed in the 7- and 14-day PS groups. The increased serum CORT and liver zinc concentrations and decreased serum zinc and apparent absorption of zinc recovered to normal concentrations 7 days away from PS exposure. The results suggest that PS could induce lower serum zinc, which might be correlated with decreased zinc absorption in the small intestine and increased liver zinc accumulation after PS exposure. The consequent effects of decreased hippocampal and serum zinc and increased CORT concentration after PS exposure on stress-related diseases await further research.
The measurement of catecholamines and their metabolites in biological samples remains a current analytical challenge, in spite of the great diversity of methodologies that have been developed throughout the years. High-performance liquid chromatography is the standard method for their separation and quantification in biological samples, either coupled with electrochemical, fluorescence, chemiluminescence or mass spectrometry detection. This review summarizes the most important physicochemical properties of catecholamines, the wide panoply of sample preparation techniques and the main issues to consider during the development of chromatographic methods. The major difficulties encountered during the optimization of these procedures are related with the high tendency of catecholamines to oxidize and the very low quantities at which they exist in biological matrices. Herein, the most important aspects that ought to be considered during collection, treatment and storage of fluid and tissue samples intended for catecholamine analysis are underlined, the chromatographic conditions are compared and the technical advantages and limitations of each detection system are discussed.
Disturbances of zinc homeostasis have been observed in several diseases, including diabetes mellitus. To further characterize the association between zinc and diabetes, we recruited 75 patients with type 1 or type 2 diabetes and 75 nondiabetic sex-/age-matched control subjects in order to analyze differences concerning human zinc transporter 8 (hZnT-8) expression, single nucleotide polymorphisms (SNPs) in the genes of hZnT-8 as well as metallothionein 1A and serum/intracellular zinc. Furthermore, we investigated the relation between insulin and zinc homeostasis in type 2 diabetic subjects and consolidated our results by in vitro analysis of the effect of insulin on cellular zinc status and by analysis of the modulation of insulin signal transduction by intracellular zinc homeostasis. Concerning the expression of hZnT-8 and the SNPs analyzed, we did not observe any differences between diabetic and control subjects. Serum zinc was significantly lower in diabetic patients compared to controls, and intracellular zinc showed the same tendency. Interestingly, type 2 diabetes patients treated with insulin displayed lower serum zinc compared to those not injecting insulin. In vitro analyses showed that insulin leads to an increase in intracellular zinc and that insulin signaling was enhanced by elevated intracellular zinc concentrations. In conclusion, we show that type 1 and type 2 diabetic patients suffer from zinc deficiency, and our results indicate that zinc supplementation may qualify as a potential treatment adjunct in type 2 diabetes by promoting insulin signaling, especially in zinc-deficient subjects.
Selenomethionine (Se-Met) is the major dietary form of selenium (Se). While Se is a required nutrient, it can also influence the physiological stress response because it stimulates greater concentrations of cortisol in blood plasma of exposed fish. However, little is known about the effects of exposure to Se on the ability to cope with a secondary stressor. In the current study, female rainbow trout were exposed to an environmentally relevant dietary concentration (8.47 mg Se/kg dry mass (dm)) of Se-Met for 126 d, after which time fish were subjected to a 3-min handling stressor and sampled at 2h and 24h post-stressor exposure. Concentrations of cortisol, cortisone, glucose, and lactate in blood plasma and concentrations of glycogen and triglycerides in liver and muscle were determined. Abundances of transcripts of proteins involved in corticosteroidogenesis were determined using quantitative RT-PCR. Concentrations of cortisol were significantly greater in blood plasma of trout exposed to Se-Met, relative to control trout sampled prior to the handling stressor. A typical response of cortisol to the handling stressor was observed in the control trout. However, trout exposed to Se-Met were unable to mount a cortisol response to the handling stressor. Concentrations of cortisone, the inactive metabolite of cortisol, were significantly greater following the handling stressor in trout exposed to Se-Met. In trout exposed to Se-Met, transcript abundance of melanocortin 2 receptor (mc2r) and peripheral benzodiazepine receptor (pbr) were greater, which is consistent with the conclusion that synthesis of cortisol was greater. However, abundances of transcripts of cytochrome P450 side-chain cleavage (p450scc) and cytochrome P450 11B1 (cyp11b1) were not significantly different between controls and Se-Met exposed trout. Exposure to Se-Met affected accumulation and tissue partitioning of glycogen and triglycerides in liver and muscle as concentrations of these energy reserves were greater in muscle, but not liver. Concentrations of glycogen and triglycerides in muscle, but not in liver, were lesser following the handling stressor suggesting that the muscle energy reserves are an important source of energy required for recovery from the handling stressor. The results of the study demonstrate that chronic exposure to dietary Se-Met elicits a stress response, but prevents a cortisol response to a secondary handling stressor, most likely due to cortisol inactivation. Moreover, exposure to Se-Met has effects on concentrations of energy reserves that are important for providing the energy necessary to cope with a secondary stressor.
Selenium levels in soil generally reflect its presence in food and the Se levels in human populations. Se food content is influenced by geographical location, seasonal changes, protein content and food processing. Periodic monitoring of Se levels in soil and food is necessary. Diet is the major Se source and approximately 80% of dietary Se is absorbed depending on the type of food consumed. Se bioavailability varies according to the Se source and nutritional status of the subject, being significantly higher for organic forms of Se. Se supplements can be beneficial for subjects living in regions with very low environmental levels of Se. Several strategies have been followed: (1) employment of Se-enriched fertilizers; (2) supplementation of farm animals with Se; (3) consumption of multimicronutrient supplements with Se. Nevertheless, detailed investigations of possible interactions between Se supplements and other food components and their influence on Se bioavailability are needed. Suppliers also need to provide more information on the specific type of Se used in supplements. In addition, research is lacking on the mechanisms through which Se is involved in hepatocyte damage during hepatopathies. Although Se potential as an antioxidant for the prevention of cardiovascular diseases (CVD) is promising, additional long-term intervention trials are necessary. As a result, indiscriminate Se supplements cannot be reliably recommended for the prevention of CVD in human beings. Some interesting findings reported an association of Se intake with a reduced prevalence and risk for prostate and colon cancer. However, random trials for other cancer types are inconclusive. As a final conclusion, the general population should be warned against the employment of Se supplements for prevention of hepatopathies, cardiovascular or cancer diseases, because benefits of Se supplementation are still uncertain, and their indiscriminate use could generate an increased risk of Se toxicity.
Little data exist on the requirements of trace metals and minerals for endurance athletes. Changes in body status of these elements must be examined before specific nutritional recommendations can be made. This study was designed to determine whether a marathon run was associated with changes in serum and urine metal and mineral concentrations.
Forty subjects who planned to complete the 1996 Houston-Tennaco marathon were recruited. Subjects had blood and urine samples collected 2 weeks prior to the race and immediately following the race. Blood and urine specimens were analyzed for copper, iron, magnesium and zinc concentrations. Blood was also analyzed for calcium concentration and ceruloplasmin activity.
Twenty-six subjects (24 male, 2 female) completed the marathon. Finish times varied between 2 hours 43 minutes and 5 hours 28 minutes. There was no significant change in serum calcium, copper or zinc concentrations or ceruloplasmin activity. Serum and urine magnesium concentration decreased significantly (19.55+/-1.73 to 16.55+/-1.53 ppm, p=0.00001; 34.02+/-8.64 to 21.80+/-12.24 ppm, p=0.003, respectively). Serum iron concentration increased significantly (1.06+/-0.48 to 1.35+/-0.42 ppm, p=0.006), while urine copper and iron concentrations were below the limits of detection, zinc concentration did not change.
Serum and urinary magnesium concentrations decrease during endurance running, consistent with the possibility of magnesium deficiency. This may be related to increased demand in skeletal muscle. Serum iron concentration increases, possibly related to tissue injury. The exact etiology for these observations, as well as their clinical significance, requires further investigation.
The purpose of this study was to assess the effect of relative exercise intensity on various plasma trace elements in euhydrated endurance athletes. Twenty-seven well-trained endurance athletes performed a cycloergometer test: after a warm-up of 10 min at 2.0 W kg⁻¹, workload increased by 0.5 W kg⁻¹ every 10 min until exhaustion. Oxygen uptake, blood lactate concentration ([La⁻](b)), and plasma ions (Zn, Se, Mn and Co) were measured at rest, at the end of each stage, and 3, 5 and 7 min post-exercise. Urine specific gravity (U(SG)) was measured before and after the test, and subjects drank water ad libitum. Fat oxidation (FAT(OXR)), carbohydrate oxidation (CHO(OXR)), energy expenditure from fat (EE(FAT)), from carbohydrates (EE(CHO)) and total EE (EE(T)) were estimated using stoichiometric equations. A repeated measure (ANOVA) was used to compare plasma ion levels at each exercise intensity level. The significance level was set at P<0.05. No significant differences were found in U(SG) between, before, and after the test (1.014±0.004 vs. 1.014±0.004 g cm⁻³) or in any plasma ion level as a function of intensity. There were weak significant correlations of Zn (r=0.332, P<0.001) and Se (r=0.242, P<0.01) with [La⁻](b), but no relationships were established between [La⁻](b), VO₂, FAT(OXR), CHO(OXR), EE(FAT), EE(CHO), or EE(T) and plasma ion levels. Acute exercise at different submaximal intensities in euhydrated well-trained endurance athletes does not provoke a change in plasma trace element levels, suggesting that plasma volume plays an important role in the homeostasis of these elements during exercise.
The present study aims to evaluate the effect of selenium supplementation on lipid peroxidation and lactate levels in rats subjected to acute swimming exercise. Thirty-two adult male rats of Sprague-Dawley type were divided into four groups. Group 1, control; group 2, selenium-supplemented; group 3, swimming control; group 4, selenium-supplemented swimming group. The animals in groups 2 and 4 were supplemented with (i.p.) 6 mg/kg/day sodium selenite for 4 weeks. The blood samples taken from the animals by decapitation method were analyzed in terms of erythrocyte-reduced glutathione (GSH), serum glutathione peroxidase (GPx) and superoxide dismutase (SOD), and plasma malondialdehyde (MDA) and lactate using the colorimetric method, and serum selenium values using an atomic emission device. In the study, the highest MDA and lactate values were found in group 3, while the highest GSH, GPx and SOD values were obtained in group 4 (p < 0,001). Group 2 had the highest and group 3 had the lowest selenium levels (p < 0,001). Results of the study indicate that the increase in free radical production and lactate levels due to acute swimming exercise in rats might be offset by selenium supplementation. Selenium supplementation may be important in that it supports the antioxidant system in physical activity.
The role of zinc in islet function has recently achieved new attention as a consequence of the identification of zinc transporter 8 (ZNT8) in islets, and the association of mutations in the gene for this zinc transporter with glucose intolerance and type 2 diabetes. ZNT8 is also an autoantigen associated with the appearance of type 1 diabetes. A number of experimental models have been employed to suggest how ZNT8 and other zinc transporters regulate beta cell insulin processing and possibly secretion. An additional role for the zinc transporters in regulating alpha cell function has been suggested. In this issue of Diabetologia, Wijesekara and colleagues, using a cell-specific Znt8 (also known as Slc30a8) knockout model, demonstrate that beta cell insulin processing and glucose tolerance is negatively affected after beta cell knock out of Znt8, whereas Znt8 knockout in alpha cells seems to have little effect on glucagon secretion or glucose tolerance. Although we are yet to see the therapeutic potential of these new findings, the area represents a field through which manipulation of islet function may eventually be possible.
Zinc is an essential trace element crucial for the function of more than 300 enzymes and it is important for cellular processes like cell division and apoptosis. Hence, the concentration of zinc in the human body is tightly regulated and disturbances of zinc homeostasis have been associated with several diseases including diabetes mellitus, a disease characterized by high blood glucose concentrations as a consequence of decreased secretion or action of insulin. Zinc supplementation of animals and humans has been shown to ameliorate glycemic control in type 1 and 2 diabetes, the two major forms of diabetes mellitus, but the underlying molecular mechanisms have only slowly been elucidated. Zinc seems to exert insulin-like effects by supporting the signal transduction of insulin and by reducing the production of cytokines, which lead to beta-cell death during the inflammatory process in the pancreas in the course of the disease. Furthermore, zinc might play a role in the development of diabetes, since genetic polymorphisms in the gene of zinc transporter 8 and in metallothionein (MT)-encoding genes could be demonstrated to be associated with type 2 diabetes mellitus. The fact that antibodies against this zinc transporter have been detected in type 1 diabetic patients offers new diagnostic possibilities. This article reviews the influence of zinc on the diabetic state including the molecular mechanisms, the role of the zinc transporter 8 and MT for diabetes development and the resulting diagnostic and therapeutic options.
The studies discussed in this paper indicate that there are significant interactions between the endocrine system and trace metals such that at physiologic and biochemical levels trace metals influence hormones and conversely, hormones influence trace metal metabolism. These interactions take place at several loci in each system and involve complex interactions at several levels of activity including secretion, transport, and binding. These reported studies, although extensive, clearly represent only an initial attempt in our understanding of the complex and varied relationships which exist between these two important systems. The future holds promise for the carrying out of many studies by which these interrelationships may be determined. By understanding interactions which focus upon relationships such as structure function, receptor binding, and receptor inhibition the roles that trace metals play in hormone action and the many ways that hormones influence the activity of trace metals can be established. (128 references are cited).
Effects of cycle ergometer exercise (approximately 75% maximum ventilatory O2 consumption for 30 min) on the concentrations of zinc and related proteins in erythrocytes and/or plasma were studied on 11 sedentary male students. Lower concentrations of total zinc and of zinc derived from carbonic anhydrase I type (CA-I) in erythrocytes were observed immediately after exercise, but they disappeared after 30 min of rest. The change in total zinc concentration in erythrocytes correlated well with that in CA-I concentration immediately after exercise, as well as after rest. The concentration of carbonic anhydrase II type (CA-II)-derived zinc did not vary substantially at any time. On the other hand, there were significant increases in the plasma concentrations of total zinc and of alpha 2-macroglobulin (alpha 2-MG)-bound zinc immediately after exercise, whereas no such effect was noted in albumin-bound zinc. A positive correlation was found between total zinc and alpha 2-MG concentrations in plasma immediately after exercise. In addition, the change in the activity of alkaline phosphatase, a zinc metalloenzyme, correlated well with that in the total zinc concentration in plasma. These results suggest that a brief physical exercise induces the movement of zinc into plasma.
The literature supports the concept that circadian changes in body temperature reflect changes in the thermoregulatory set point. We were interested in studying the relationship between the circadian rhythm in body temperature and 24-h variations in plasma concentrations of iron, zinc, circulating leukocyte counts, and plasma interleukin 1 (IL-1) activity. Eight healthy men were studied for two separate 48-h sessions. Rectal temperature, plasma iron and zinc concentrations, plasma IL-1 activity, circulating leukocyte counts, and several other blood variables were monitored. Circadian rhythms in temperature, trace metals, and various leukocyte populations were demonstrated. The 24-h pattern of changes in plasma concentrations of iron and zinc approximate an inverse relationship with rectal temperature. Although we were unable to detect any IL-1 activity in human plasma collected at 4-h intervals, the daily changes in plasma trace metal concentrations and the variations in leukocyte populations may provide indirect evidence for a daily variation in local (e.g., in liver) or central nervous system release of IL-1.
Reference values are proposed for the concentrations of As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Pb, Se, and Zn in whole blood, blood serum, urine, milk, liver, and hair from adult human subjects. For F, I, and Ni, it was not possible to evaluate reference intervals for all the specimens mentioned above. For several elements, including Al, B, Br, Cs, Li, Rb, U, and V, the present status of the literature does not provide an adequate basis for formulating baseline concentrations; therefore, results from selected investigations are listed for information only. For elements such as Cu, Fe, and Zn, which are known to be homeostatically controlled, the concentrations in whole blood and blood serum follow a gaussian-like frequency distribution, and we could consider both median and mean values for evaluation. On the other hand, elements whose concentrations in tissues and body fluids are influenced by dietary availability (e.g., As and Se) or environmental factors (e.g., Cd, Hg, and Pb) show wide scatter. In these cases, the median appeared to be a better indicator of the central tendency than the mean, when different populations are involved. These points are illustrated.
To study the physiologic basis of variability of physical performance in the laboratory, ten male subjects were studied once a week, during a 9-12 month period. Previously, the reference maximal work load attained (Wref) was determined in each subject. The test protocol of the actual study was based on the individual Wref and started at 70% Wref for 5 min whereupon the work load was increased by 5% Wref every 2.5 min to exhaustion. The maximal work load attained (Wmax) was considered as the test performance. Heart rate, respiratory variables, oxygen uptake (VO2), and blood lactate concentration were determined at each work load. The rate of perceived exertion during submaximal and maximal work was also scored. In all subjects, Wmax and VO2max varied randomly, while the coefficient of variation in VO2max (4.20% - 11.35%) exceeded that in Wmax (2.95%-6.83%). No seasonal influences on VO2 max and Wmax were observed. In all subjects the physiologic variables, when plotted as a function of external work load, were shifted to the right with higher Wmax values and to the left with lower Wmax values. With lower Wmax values, the rate of perceived exertion during submaximal work tended to increase. The results suggest that the magnitude of physiologic responses to exercise is related to relative work load and that variability of physical performance is related to changes in gross mechanical efficiency.
Physical exercise leads to many metabolic, cardiovascular, and muscular changes in the body. The trace elements (TE) zinc and copper are directly involved, as enzymatic cofactors, in many of these processes, especially those related to nutrients metabolism, oxygen transport, and formation of usable energy. The effects of high-intensity physical exercise on plasma levels of CU2+ and Zn2+ in 19 subjects are investigated (9 males and 10 females). Plasma copper concentration decreases, and plasma zinc concentration increases, after exercise, in both sexes. After 30 min recovery, both TE concentration values shifts-toward rest values in both sexes.
These results only partially agree with literature data, probably because we used the treadmill exercise, which makes many muscles work, whereas other authors made their subjects perform a cycloergometer exercise. Physical exercise causes a marked redistribution of TE (copper and zinc) between body stores, bloodstream, and tissues. The condition of high metabolism may lead to a deficiency of TE, requiring supplementation in order to maintain high level performance.
Thymic atrophy and lymphopenia are immunological hallmarks of many forms of malnutrition including deficiencies in zinc. Extreme thymic atrophy (70-80%) along with a 50% loss of splenocytes in mice maintained on a zinc deficient diet (ZD) for 30 days suggested that the deficiency might be altering lymphopoiesis or the production of new lymphocytes by the bone marrow. As shown herein, mice who were marginally zinc deficient being 72-75% the body weight of adequately fed controls, exhibited a 50% decline in pre B-cells and a 25% decline in immature B-cells. The mature B-cells of the marrow appeared fairly resistant to effects of suboptimal zinc intake. Interesting, this pattern was similar to results obtained by treating bone marrow cells with levels of glucocorticoids analogous to those found in nutritionally deficient rodents. Furthermore, these same concentrations of steroids were shown to induce significant levels of apoptosis or cell death among pre and immature B-cells which accounted for their declining numbers subsequent to exposure to glucocorticoid. In order to better ascertain the potential role of glucocorticoids generated during zinc deficiency on lymphopoietic processes, adrenalectomies were performed in an attempt to remove glucocorticoids from the equation. Subsequently, adrenalectomized and sham operated mice were placed on a ZD or zinc adequate diet (ZA). Levels of steroids at the time of sacrifice were elevated six fold in non-adrenalectomized ZD mice compared to ZD adrenalectomized mice. Removal of the adrenal gland protected the thymus of ZD mice from atrophy and also provided substantial protection of lymphopoietic processes.(ABSTRACT TRUNCATED AT 250 WORDS)
This study reports plasma and total blood cell (TBC) Cu and Zn levels of 16 runners before and after a marathon race. All the pre-race plasma values were in the normal range, while the TBC Cu level was 29.3% (P < 0.01) lower and the TBC Zn level was 29.5% (P < 0.01) higher than mean values of the control group. The run induced a significant decrease in TBC Cu concentration during the days following the race and a light increase in plasma Cu values. It caused a significant increase in TBC Zn concentration at the end of the race (followed by a decrease 24 hours later) without plasma Zn variations. These data show that intense physical exercise could modify trace-element metabolism.
Selenium which has been recognised as an essential trace element for mammals and humans is part of the enzyme glutathione peroxidase (GSHPx) and of other selenium-dependent enzymes. GSHPx protects the organism from oxidative damage. Supposing that the formation of peroxides is enhanced in athletes during a marathon run the question arose whether the selenium concentrations in the blood plasma and the GSHPx activities in the erythrocytes are changed. Our experiments were performed with 13 athletes completing a marathon. Blood probes were taken before, immediately after and two hours after the endurance event. No significant changes in the selenium concentrations of the blood plasma probes nor of the enzyme glutathione peroxidase activities of the erythrocytes were observed during the experiments. The selenium concentrations in the plasma: 77.7 +/- 20.8 micrograms/l and the GSHPx activities of the erythrocytes 18.2 +/- 7.4 U/g Hb were within normal clinical range. Symptoms of selenium deficiency could not be detected. In order to answer the question of whether the selenium concentrations in the blood of the athletes represent an optimal level for preventing enhanced formation of peroxides, intervention studies are needed, including measurement of more parameters of lipid peroxidation.
Significant, sexual dimorphisms exist in counterregulatory responses to commonly occurring stresses, such as hypoglycemia, fasting, and cognitive testing. The question of whether counterregulatory responses differ during exercise in healthy men and women remains controversial. The aim of this study was to determine whether a sexual dimorphism exists in neuroendocrine, metabolic, or cardiovascular responses to prolonged moderate exercise. Sixteen healthy (eight men and eight women) subjects matched for age (28+/-2 yr), body mass index (22+/-1 kg/m2), nutrient intake, and spectrum of physical fitness were studied in a randomized fashion during 90 min of exercise on a cycle ergometer at 80% of their anaerobic threshold (approximately 50% VO2 max). Respiratory quotient and oxygen consumption relative to body weight were identical in men and women. Glycemia was equated (5.3+/-0.2 mmol/L) during exercise via an exogenous glucose infusion. Gender had significant effects on counterregulatory responses during exercise. Arterialized epinephrine (1.05+/-0.2 vs. 0.45+/-0.04 nmol/L), norepinephrine (9.2+/-1.1 vs. 5.8+/-1.1 nmol/L), and pancreatic polypeptide (52+/-6 vs. 37+/-6 pmol/L) were significantly (P<0.01) increased in men compared to women, respectively. Plasma glucagon, cortisol, and GH levels responded similarly in men and women. Insulin values were higher at baseline in men and fell by a greater amount to reach similar levels during exercise compared to those in women. Endogenous glucose production, measured with [3-3H]glucose was similar in men and women. Carbohydrate oxidation was significantly increased in men relative to women (21.2+/-2 vs. 15.6+/-2 mg/kg fat free mass x min; P<0.05). Despite reduced sympathetic nervous system (SNS) drive, lipolytic responses were increased in women. Arterialized blood glycerol (215+/-30 vs. 140+/-20 micromol/L), beta-hydroxybutyrate (54+/-9 vs. 25+/-10 micromol/L), and plasma nonesterified fatty acids (720+/-56 vs. 469+/-103 micromol/L) were significantly (P<0.01) increased in women. In keeping with increased SNS activity, systolic blood pressure and mean arterial pressure were significantly increased (P<0.01) in men. In summary, this study demonstrates that a significant sexual dimorphism exists in neuroendocrine, metabolic, and cardiovascular counterregulatory responses to prolonged moderate exercise in man. We conclude that during exercise, men have increased autonomic nervous system (epinephrine, norepinephrine, pancreatic polypeptide), cardiovascular (systolic, mean arterial pressure) and certain metabolic (carbohydrate oxidation) counterregulatory responses, but that women have increased lipolytic (glycerol, nonesterified fatty acids) and ketogenic (beta-hydroxybutyrate) responses. Women may compensate for diminished SNS activity during exercise by increased lipolytic responses.
The hormonal responses of nine male, strength athletes to strength exercise were examined. The athletes performed one moderate- and one high-intensity strength exercise workout. In the high-intensity workout, the load was 100% of each subject's three-repetition maximum (3-RM) for squats and front squats, and 100% of each subject's six-repetition maximum (6-RM) for leg extensions. In the moderate-intensity workout, the load was 70% of the high-intensity protocol. Rest periods between sets were 4-6 min for both workouts. Blood samples were taken before, 30 min into, and every 15 min for the 1st h after exercise, and then 3, 7, 11, 22 and 33 h after exercise, thus allowing examination of both the acute and prolonged hormonal responses. Blood samples were analyzed for testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH), cortisol, adrenocorticotrophic hormone (ACTH), growth hormone (GH), insulin-like growth factor (IGF-1), insulin, sex hormone binding globulin, creatine kinase, total protein, glucose and lactate. The acute responses of testosterone and cortisol were greater during the high-intensity protocol as compared to the moderate-intensity protocol. The cortisol response was associated with an increase in ACTH concentration. LH and FSH showed no response to either protocol. Acute GH responses were not different between protocols. There were great inter-individual differences in acute GH responses to both protocols. There were no significant differences between protocols with regard to prolonged responses for any hormone. In both trials, IGF-1 concentrations were significantly lower at 0800 hours the morning after exercise as compared to concentrations found at 0800 hours the morning before exercise. The mechanisms responsible for reducing IGF-1 concentration in these trials are unclear, and it is not known if this reduction observed 22 hours after exercise is of physiological significance.
Plasma selenium reference values from healthy donors in the metropolitan area of Barcelona are determined. A random sample from 156 healthy adults (control group) is analysed by using electrothermal atomic absorption spectrometry with Zeeman effect background correction. The relationship between several pathologies and Se content is also evaluated. Se content from 64 samples from subjects with chronic renal failure and 54 from subjects suffering from several malignancies are determined and the results are compared to the reference values. Moreover, Se contents are determined and compared in two groups of children, healthy (19 samples) and children of mothers infected with HIV-1 (16 samples). In the control group, Se plasma concentration ranges between 50 and 145 microg x L(-1) (82.2 +/- 17.5 microg x L(-1)). Significantly lower values are found in the two pathologies studied (malignancy and chronic renal failure), compared to the control group. However, no significant differences in Se content are found between the two groups studied regarding malignancy and chronic renal failure. In children of mothers infected with HIV-1, Se status is significantly lower than that of healthy children.
The aim of the present study was to investigate how zinc (Zn) deficiency and supplementation affect glycogen content of the liver and plasma lactate and leptin levels of rats performing acute swimming exercise just before the blood samples were obtained. Four sets of 10 rats each served as the (1) Zn-deficient group, (2) Zn-supplemented group, (3) swimming controls, and (4) normal controls. Plasma lactate levels of Zn-deficient animals were significantly higher than those in the other three groups (p<0.01), and those in the swimming controls (group 3) were significantly higher than in the Zn-supplemented animals, group 2 (p<0.01). The plasma glucose of the Zn-deficient group was significantly higher than all other groups (p<0.01) and that of group 2 was significantly lower than group 4 (p<0.01). Glycogen levels in liver of the Zn-deficient animals was significantly lower than groups 2 and 4 (p<0.01), and, in turn, were higher than for group 3 (p<0.01). The plasma leptin and Zn levels of group 1 were significantly lower than in all other groups (p<0.01). These results suggest that Zn deficiency exerts a negative influence in the above-mentioned parameters and that Zn supplementation has the opposite effect.
Exercise initiates a coordinated series of physiological responses, including hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system activation, that, in combination, lead to the appropriate selection and utilization of metabolic substrates. Physical activity acts as a powerful stimulus for the hypothalamic-pituitary axis, leading to the liberation of several neuroendocrine hormones. The nature of this stimulation varies according to the kind of exercise (intensity, duration, aerobic, strength) and subject characteristics (gender, previous training), as well as depending on the time of the day and meal ingestion. As a whole, the neuroendocrine responses to exercise represent an accurate regulator of fuels (glucose, free fatty acids) homeostasis in a special situation characterized by a drastic increase of the energy requirements at muscle level. In this article the current knowledge about this topic is reviewed.
Molecular and cellular studies have demonstrated several roles for zinc (Zn) in insulin production and the consequent actions of insulin on metabolism. Clinical and epidemiological studies suggest that reduced Zn status is associated with diabetes. Investigations of Zn in rodent models of diabetes have provided a valuable link for understanding the molecular, cellular, clinical and epidemiological observations in the context of inter-organ metabolism and the metabolic disturbances of diabetes. This review highlights some of the current knowledge and future research directions for the role of Zn in the pancreas and diabetes based on rodent studies and experimental manipulations of Zn. Overall, Zn supplementation is effective for preventing or ameliorating diabetes in several rodent models of Type 1 and Type 2 diabetes. Studies with chemically-induced Type 1 diabetes indicate that the protective effects of Zn involve antioxidant mechanisms whether it is Zn alone (as an antioxidant), Zn induction of metallothionein or Zn inhibition of redox-sensitive transcription factors. Further studies are needed to identify the mechanism(s) for Zn protection in Type 2 diabetes, including pancreatic and peripheral effects. Experimental manipulations of Zn status in rodent models of diabetes provide a valuable approach to explore mechanisms for the protective effects of Zn; however, long term clinical studies establishing safety (lack of toxicity) and efficacy are required before any recommendations can be made for people with diabetes.
The effects of exercise training on hypothalamo-pituitary-adrenal (HPA) function are unclear. We investigated whether pituitary-adrenal adaptation during exercise training is mediated by changes in neuropeptide and corticosteroid receptor gene expression in the brain and pituitary. Sprague-Dawley rats were subject to either daily swimming (DS) or sham exercise (SE) for 45 min/day, 5 days/week, for 2 (2W), 4 (4W), or 6 wk (6W) (n = 7-10/group). Corticosterone (Cort) and catecholamine responses during swimming were robust at 6W compared with 2W and 4W, indicating that HPA response to exercise during training is not attenuated when absolute intensity is progressively increased. In DS, basal (morning) plasma ACTH and Cort levels increased from 2W to 4W but plateaued at 6W, whereas in SE, they increased from 4W to 6W, with 6W values higher than in DS. In DS, there was a transient decrease in glucocorticoid receptor (GR) mRNA in the paraventricular nucleus (PVN) and pituitary and a transient increase in corticotrophin-releasing hormone (CRH) mRNA. In contrast, hippocampal mineralocorticoid receptor mRNA and PVN GR mRNA decreased from 4W to 6W in SE, with 6W values lower than in DS. These findings suggest that exercise training prevents an elevation in basal pituitary-adrenal activity potentially via transient alterations in the gene transcription of PVN and pituitary GR as well as CRH to suppress central drive to the HPA axis. In contrast, the increase in basal pituitary-adrenal activity with repeated sham exercise appears to be associated with decreases in hippocampal MR and PVN GR mRNA expression.