Article

Decreases in Ovarian Cytochrome P450c17?? Activity and Serum Free Testosterone after Reduction of Insulin Secretion in Polycystic Ovary Syndrome

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Abstract

Insulin resistance and increased ovarian cytochrome P450c17 alpha activity are both features of the polycystic ovary syndrome. P450c17 alpha, which is involved in androgen biosynthesis, has both 17 alpha-hydroxylase and 17,20-lyase activities. Increased activity of this enzyme results in exaggerated conversion of progesterone to 17 alpha-hydroxyprogesterone in response to stimulation by gonadotrophin. We hypothesized that hyperinsulinemia stimulates ovarian P450c17 alpha activity. We measured fasting serum steroid concentrations and the response of serum 17 alpha-hydroxyprogesterone to leuprolide, a gonadotrophin-releasing hormone agonist, and performed oral glucose-tolerance tests before and after oral administration of either metformin (500 mg three times daily) or placebo for four to eight weeks in 24 obese women with the polycystic ovary syndrome. In the 11 women given metformin, the mean (+/- SE) area under the serum insulin curve after oral glucose administration decreased from 9303 +/- 1603 to 4982 +/- 911 microU per milliliter per minute (56 +/- 10 to 30 +/- 6 nmol per liter per minute) (P = 0.004). This decrease was associated with a reduction in the basal serum 17 alpha-hydroxyprogesterone concentration from 135 +/- 21 to 66 +/- 7 ng per deciliter (4.1 +/- 0.6 to 2.0 +/- 0.2 nmol per liter) (P = 0.01) and a reduction in the leuprolide-stimulated peak serum 17 alpha-hydroxyprogesterone concentration from 455 +/- 54 to 281 +/- 52 ng per deciliter (13.7 +/- 1.6 to 8.5 +/- 1.6 nmol per liter) (P = 0.01). The serum 17 alpha-hydroxyprogesterone values increased slightly in the placebo group. In the metformin group, the basal serum luteinizing hormone concentration decreased from 8.5 +/- 2.2 to 2.8 +/- 0.5 mlU per milliliter (P = 0.01), the serum free testosterone concentration decreased from 0.34 +/- 0.07 to 0.19 +/- 0.05 ng per deciliter (12 +/- 3 to 7 +/- 2 pmol per liter) (P = 0.009), and the serum sex hormone-binding globulin concentration increased from 0.8 +/- 0.2 to 2.3 +/- 0.6 microgram per deciliter (29 +/- 7 to 80 +/- 21 nmol per liter) (P < 0.001). None of these values changed significantly in the placebo group. In obese women with the polycystic ovary syndrome, decreasing serum insulin concentrations with metformin reduces ovarian cytochrome P450c17 alpha activity and ameliorates hyperandrogenism.

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... Consequently, in PCOS patients, MF-induced potentiation of the metabolic-improving effects of GLP-1 agonists may also increase their restorative effects on the menstrual cycle and fertility. One of the main mechanisms of the restorative effect of MF on ovarian function, ovulation and pregnancy in PCOS women mediates through the pronounced antiandrogenic effect of MF, both in monotherapy and in combination with other drugs [141,152,[171][172][173][174][175][176][177][178][179]. ...
... This is supported by the data on the increased secretion of androstenedione and the elevated basal and LH-stimulated production of testosterone in cultured ovarian theca and stroma cells incubated in the presence of insulin [204,206]. A decrease in insulin secretion induced by MF (500 mg three times daily) in obese PCOS women led to inhibition of cytochrome P450c17α activity in the ovaries, decreasing the basal levels of 17α-hydroxyprogesterone and the levels of this hormone stimulated by leuprolide, a gonadotropin-releasing hormone (GnRH) analogue [171]. ...
... In PCOS, the blood levels of androgen and sex hormone-binding globulin (SHBG) are reduced, which leads to an increase in free testosterone level and free androgen index. As early as the 1990s, hyperinsulinemia was found to be an important factor for the suppression of SHBG production in PCOS [171,209,210]. Overweight plays a key role in this process, as supported by observation that weight loss in obese PCOS women induced by a low-calorie diet leads to a restoration of SHBG levels, which may be due to a decrease in IR and insulin levels [211]. ...
Article
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Metformin (MF), a first-line drug to treat type 2 diabetes mellitus (T2DM), alone and in combination with other drugs, restores the ovarian function in women with polycystic ovary syndrome (PCOS) and improves fetal development, pregnancy outcomes and offspring health in gestational diabetes mellitus (GDM) and T2DM. MF treatment is demonstrated to improve the efficiency of in vitro fertilization and is considered a supplementary drug in assisted reproductive technologies. MF administration shows positive effect on steroidogenesis and spermatogenesis in men with metabolic disorders, thus MF treatment indicates prospective use for improvement of male reproductive functions and fertility. MF lacks teratogenic effects and has positive health effect in newborns. The review is focused on use of MF therapy for restoration of female and male reproductive functions and improvement of pregnancy outcomes in metabolic and endocrine disorders. The mechanisms of MF action are discussed, including normalization of metabolic and hormonal status in PCOS, GDM, T2DM and metabolic syndrome and restoration of functional activity and hormonal regulation of the gonadal axis.
... The progestogen component of OCP has been associated with dyslipidemia in OCP users [67]. Although some of the OCPs looked to elevate HDL levels significantly [67,68], the magnitude of the impact was generally small, and there was significant variation between the cohorts studied [69]. The usage of the OCP and the adverse effects it has on metabolic markers is vital in obese PCOS patients. ...
... Metformin is the most widely researched insulinlowering medication in the treatment of PCOS. For 20 years, metformin, a biguanide antihyperglycemic, has been utilized to treat PCOS [69]. Metformin enhances insulin sensitivity by decreasing gluconeogenesis and lipogenesis and improving glucose metabolism in the liver, skeletal muscle, adipose tissue, and ovaries [77]. ...
Article
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... The severity of metabolic syndrome and the phenotype of PCOS are strongly associated with the degree of hyperandrogenism and hyperinsulinemia [15,16]. Decreasing plasma insulin level and improving insulin resistance in patients with PCOS not only benefit hyperandrogenism and ovulation but also reduce cardiovascular risks [1,12,17]. Besides lifestyle modification, metformin is commonly used as an insulin sensitive agent that reduces fasting glucose, improving insulin resistance in patients with PCOS [18]. ...
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... Changes in testosterone and insulin (both basal and glucose-stimulated) concentrations may be significantly correlated, regardless of body weight variations. 10,18 Recent studies have suggested that hyperinsulinaemia may be responsible for increased activity of the ovarian cytocrome P450cl7 system, which has been indicated as playing a key role in determining ovarian hyperandrogenism in many PCOS women. 2 Reduction of insulin concentrations by metformin 13 and diet has been demonstrated to reduce this enzyme activity and, consequently, ovarian androgen production. Recently we found that obese PCOS women undergoing hypocaloric dietary treatment coupled with antiandrogen (cyproterone acetate plus ethynilestradiol) or metabolic drugs (such as metformin or dexfenfluramine) had a similar degree of weight loss and also a similar decrease testosterone serum concentrations (unpublished data). ...
Article
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Obesity (with body mass index > 30 kg/m 2) is an important pathological factor which influences the development of hyperandrogenism in women with polycystic ovary syndrome (PCOS). Obese women, particularly those with central obesity, have more difficulty to conceive per cycle. Obese women suffer with irregular menstrual cycle which affect the body hormonal system. Thus obesity affect ovulation, endometrial growth and nidation There fore weight loss have several beneficial effects upon clinical, endocrinological and metabolic features of obese women presenting with PCOS. In fact, weight loss is associated with a significant improvement in menses abnormalities, ovulation and fertility rates, and with a reduction of hyperandrogenism, hyperinsulinaemia, and altered gonadotrophin pulsatile secretion. The central role of improved insulin concentrations and insulin-resistant state is emphasized by the fact that similar effects can be achieved by both short-and long-term administration of metformin, an insulin lowering drug which ameliorates peripheral insulin action in non-diabetic insulin resistant states. We therefore recommend weight loss as a first-line therapeutic option in all women with obesity and Polycystic ovary syndrome (PCOS). And it may be chive by both pharmacological (drug used to suppress apatite) and non pharmacological (life style modification, diet etc.) treatment.
... It regulates the glucose level, unlike other insulin-regulating drugs which lead to either hypoglycemia or hyperglycemia as its side effect [47]. Metformin functions indirectly by lowering the insulin level with a decrease in CYP17 cytochrome activity which is involved in the production of androgens and also increases the SHBG further decrease in the free testosterone [48,49]. The effects of metformin also include slight improvement in the lipid profile of PCOS patients [50,51]. ...
Article
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Polycystic ovarian syndrome (PCOS) is a heterogeneous endocrine disorder with the underline indication of ovarian cysts, anovulation, and endocrine variation affecting the women. According to the World Health Organization (WHO) estimation revealed over 116 million women (3.4%) are affected by PCOS worldwide. The predisposing risk factors include genetics, neuroendocrine, lifestyle/environment, obesity that contributes to the development of PCOS. The pathophysiological aspect of PCOS mainly focuses on hormonal dysfunction, insulin resistance, and hyperandrogenism leading to impaired folliculogenesis which arise the risk for associated comorbidities like endometrial cancer, type II diabetes. This review highlights a brief overview of risk and pathophysiological treatment with drugs acting on anovulation, infertility plus clinical symptoms of PCOS.
... Most authors however share the opinion that insulin resistance is the primary defect and hyperandrogenemia is secondary to that. Hyperinsulinemia appears to play an important pathogenic role in the hyperandrogenism and anovulation of both obese and lean women with PCOS [33,34]. Insulin can directly stimulate androgen secretion and/or increase lutein hormone (LH)-induced androgen secretion from the theca-cells [35,36], increase the amplitude of LH pulsatile secretion [34], decrease liver production of sex hormone binding globulin (SHBG) [37] (Figure 1). ...
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... Its role as an insulin sensitizer has led to its widespread use in PCOS in conjunction with other ovulation inducing agents. 12 However, there are very limited use of other insulin sensitizing agents like Dchiroinositol, rosiglitazone or pioglitazone, and are not discussed here. Metformin alone could significantly increase the ovulation rate vs placebo (23% vs 13%), while it does not significantly increase the pregnancy or live birth rate. ...
Article
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Polycystic ovarian syndrome (PCOS) is the most common problem related to infertility among women. This review looked into the evidence and options available for ovulation induction. The management protocol and their respective efficacy was looked into during the write up of the review. Weight reduction, along with metformin therapy are the initial and efficient way to regain ovulation among obese female. This should be complemented by use of first line medicine like aromatase inhibitors and selective estrogen receptor modulators. The first line is effective in significant proportion of female to induce ovulation and increase live birth rate. However, for those not responding should initially undergo the use of gonadotropins and ovarian drilling. Finally, controlled ovarian stimulation and in vitro fertilization should be considered as it is an invasive, expensive and there are risks of ovarian hyperstimulation and multiple gestation.
... Moreover, PCOS women display increased presence of steroidogenic enzymes in thecal and granulosa cells, including 17α-hydroxylase [59]. Therefore, treating PCOS women with insulin-sensitizing agents such as metformin reduces 17α-hydroxylase activity, allowing physiological steroidogenesis [60]. Concomitantly, the improved signals of insulin, that would lead to physiological signals via DCI, would also allow the recovery of the physiological expression and activity of aromatase and 3β-HSD. ...
Article
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D-chiro-inositol (DCI) is a natural compound detectable in cell membranes, which is highly conserved as a biological signaling molecule. In mammals, its function is primarily characterized in the intracellular transduction cascade of insulin. In particular, insulin signal promotes the release of pivotal DCI-containing molecules. In fact, impaired release of DCI is a common feature of insulin-resistant tissues, and insulin-sensitizing pharmaceuticals induce higher concentrations of free DCI. Moreover, it also plays important roles in several other processes. DCI is involved in the regulation of steroidogenesis, due to its regulatory effects on steroidogenic enzymes, including 17α-hydroxylase, 3β-hydroxysteroid dehydrogenase, and aromatase. Such regulation of various enzymes indicates a mechanism by which the body regulates different processes via a single molecule, depending on its concentration. DCI also reduces the expression of integrin β3, which is an adhesion molecule involved in embryo implantation and cellular phenomena such as survival, stemness, and invasiveness. In addition, DCI seems to have important anti-inflammatory activities, like its 3-O-methyl-ether, called pinitol. In vitro evidence demonstrates that treatment with both compounds induces a reduction in pro-inflammatory factors—such as Nf-κB—and cytokines—such as TNF-α. DCI then plays important roles in several fundamental processes in physiology. Therefore, research on such molecule is of primary importance.
... The major endocrine disruption is excessive androgen secretion or activity, and a large proportion of women also have abnormal insulin activity. Many body systems are affected in polycystic ovary syndrome, resulting in several health complications, including menstrual dysfunction, infertility, hirsutism, acne, obesity and metabolic syndrome (Nestler and Jakubowicz, 1996;1998). Women with this disorder have an established increased risk of developing type-II diabetes and a still debated increased risk of cardiovascular disease. ...
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Normal pregnancy is associated with metabolic changes leading to decreased insulin sensitivity and reduced glucose tolerance. However, 3-5% of pregnant women proceed to develop gestational diabetes mellitus (GDM). Researchers elsewhere studied the use of metformin in many fields and the benefit to risk balance of using metformin during pregnancy and the risk of fetotoxic. In this study, the use of Metformin to control Glucose in pregnant women with gestational diabetes mellitus (GDM) was examined and its safety use during the first trimester of pregnancy was evaluated.A group of pregnant patients with gestational diabetes mellitus from the first trimester of pregnancy, non-smoking with no family history of congenital malformation disease, aged between (20-45 years) and have no liver diseases and who had indicating good compliance at more than one visit over several month until delivery put on Metformin were participated in this trial. The results show that all the studied group of pregnant women using metformin 500mg daily delivered healthy babies.Meta-analysis by mother risk program showed no increase in incidence of malformations by use of Metformin during the first trimester of pregnancy.A hundred outpatients were participated in the survey on the general knowledge and awareness of diabetic patients to their illness and medication used their aged between 20-40 years old. It was realized that 90% of physicians are not giving patients full information about their illness and the use of Metformin during pregnancy. Also, about 65% of patients did not know about the nutritionist in the hospital, the right control diet for diabetes, courses on first aid, rapid diagnosis of poisoning and follow the written procedures to dealing with such cases.
... Some studies have shown that metformin, by decreasing serum insulin level, reduces ovarian cytochrome P450c17a activity and ameliorates the hyperandrogenism of PCOS women. 47,48 Also other studies 25,32 found that the serum leptin concentrations followed the same pattern as the serum testosterone concentrations during metformin, suggesting the possibility that leptin and androgen synthesis are related which is in agreement with our study. The direct effect of leptin on ovarian steroidogenesis is possible because, messenger RNA for leptin receptors has been found in both thecal and granulosa cells of the ovaries. ...
Article
The relationship between serum leptin, insulin level, insulin sensitivity and other hormonal parameters in polycystic ovary syndrome (PCOS) is controversial. This study was conducted to evaluate the effect of metformin on serum leptin and testosterone level and insulin sensitivity in patients with PCOS in Mosul City in Iraq. A group of 31 women with PCOS of reproductive age who used metformin for more than three months (metformin users), with another age and body mass index (BMI)-matched group of 31 women with PCOS who did not use metformin (metformin non-users), were included in this study. From each patient, a 10 ml fasting blood sample was taken. The serum was used to estimate the serum glucose, leptin and insulin concentration using commercially available kits whereas; body mass index (BMI) were calculated as weight in kilograms divided by the squared height in meters and insulin resistance were calculated using Homeostasis Model Assessment (HOMA) index. The results of this study found that about half (51.04 %) of the studied PCOS patients (with and without metformin therapy) were obese. There was a non significant difference between fasting serum glucose (FSG) level but a significant lower level of fasting serum insulin and HOMA-IR index, also there were a non significant difference between serum leptin and testosterone level in metformin users in comparison with non-users. Fasting insulin level of all the studied PCOS women found to be within normal range, however the serum leptin level was found to be above the normal range. There were significant positive correlations between insulin, HOMA-IR and leptin with BMI, testosterone with insulin, HOMA-IR and with leptin but a non significant correlation between insulin with leptin, HOMA-IR with leptin and testosterone with BMI. It has been concluded that metformin therapy for more than three months has beneficial role in lowering fasting serum insulin level and HOMA-IR in non insulin resistant PCOS patients with a significant correlation with BMI and serum testosterone level but not with serum leptin level
... IR, the resulting hyperinsulinemia, and increased androgen levels influence each other, and it is difficult to determine which phenomenon occurs first ( Figure 4) [61]. Insulin acting on ovarian theca cells increases androgen synthesis by increasing activity of the cytochrome P450C17α, which has 17-hydroxylase and 17,20-lyase activities [62]. Insulin acts on ovarian theca cells by further increasing LH stimulatory effect [63]. ...
Article
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Insulin resistance is documented in clamp studies in 75% of women with polycystic ovary syndrome (PCOS). Although it is not included in the diagnostic criteria of PCOS, there is a crucial role of this metabolic impairment, which along with hormonal abnormalities, increase each other in a vicious circle of PCOS pathogenesis. Insulin resistance in this group of patients results from defects at the molecular level, including impaired insulin receptor-related signaling pathways enhanced by obesity and its features: Excess visceral fat, chronic inflammation, and reactive oxygen species. While lifestyle intervention has a first-line role in the prevention and management of excess weight in PCOS, the role of anti-obesity pharmacological agents in achieving and maintaining weight loss is being increasingly recognized. Glucagon-like peptide-1 receptor agonists (GLP1-RAs) not only act by reducing body weight but also can affect the mechanisms involved in insulin resistance, like an increasing expression of glucose transporters in insulin-dependent tissues, decreasing inflammation, reducing oxidative stress, and modulating lipid metabolism. They also tend to improve fertility either by increasing LH surge in hypothalamus-pituitary inhibition due to estrogen excess connected with obesity or decreasing too high LH levels accompanying hyperinsulinemia. GLP1-RAs seem promising for effective treatment of obese PCOS patients, acting on one of the primary causes of PCOS at the molecular level.
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Polycystic ovary syndrome (PCOS) is the most frequent endocrine-metabolic disorder among women at reproductive age. The diagnosis is based on the presence of at least two out of three criteria of the Rotterdam criteria (2003). In the last decades, the dysmetabolic aspect of insulin resistance and compensatory hyperinsulinemia have been taken into account as the additional key features in the etiopathology of PCOS, and they have been widely studied. Since PCOS is a complex and multifactorial syndrome with different clinical manifestations, it is difficult to find the gold standard treatment. Therefore, a great variety of integrative treatments have been reported to counteract insulin resistance. PCOS patients need a tailored therapeutic strategy, according to the patient’s BMI, the presence or absence of familiar predisposition to diabetes, and the patient’s desire to achieve pregnancy or not. The present review analyzes and discloses the main clinical insight of such complementary substances.
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Polycystic ovarian syndrome (PCOS) is a fairly common disease that occupies one of the leading positions among the reasons of endocrine infertility. Women with this diagnosis have an increased risk of developing diabetes mellitus, cardiovascular disease, metabolic syndrome (dyslipidemia, decreased sensitivity to peripheral tissue insulin, hyperinsulinemia). Currently, a step-by-step and individual approach to treatment has been applied, including both conservative treatments and surgical ones.
Chapter
Polycystic ovary syndrome is a common endocrinopathy, with hyperandrogenism being the cardinal feature, but which is also highly associated with insulin resistance and metabolic disorders. Despite present evidence, the exact role of insulin resistance and associated compensatory hyperinsulinemia in PCOS hyperandrogenism is still debated. The existence of non-insulin-resistant PCOS phenotype in a subset of women with typical hyperandrogenism suggests that insulin resistance is not a requisite for the development of this syndrome. Nevertheless, several lines of emerging evidences suggest that impairment in insulin signaling may be implicated in androgen overproduction at the level of androgen-producing organs. After an historical review, this chapter will address in vivo studies assessing insulin action in women with PCOS. It will focus on the main results describing the effects of insulin resistance on hyperandrogenism in PCOS and then discuss the different insulin signaling anomalies occurring in both metabolic and mitogenic insulin signaling pathways. In addition, how these signaling dysfunctions may hypothetically influence androgen synthesis in these women will be addressed. Finally, the lipotoxicity theory will be discussed. This chapter will describe how increased exposure of lean organ to circulating fatty acids could lead to the development of insulin resistance in PCOS, as it does in other conditions such as type 2 diabetes. More importantly, literature suggesting potential direct effects of lipotoxicity on androgen production and potential underlying mechanisms will be presented. Through this chapter, whether insulin resistance may be the main cause of hyperandrogenism in PCOS or whether it could be the consequence of an upstream dysfunction, namely, lipotoxicity will be assessed.
Chapter
Anti-Mullerian hormone (AMH) is often elevated in patients with polycystic ovary syndrome (PCOS). There is increasing evidence that high serum AMH is not only a marker of the disorder but plays a critical role in disrupting normal folliculogenesis. This chapter explores the contribution of elevated AMH levels to the chronic anovulation which often accompanies PCOS, currently available treatment modalities, and future therapeutic targets using AMH analogues for improving ovulatory function in patients with PCOS.
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Polycystic ovary syndrome (PCOS) is the most common endocrine and metabolic disease in women of reproductive age. PCOS is characterized by ovulatory disruption, which can lead to infertility. Patients with PCOS are also more likely to have poor pregnancy outcomes. For obese women, lifestyle interventions are recommended first, which have general health benefits. For women who have difficulty changing their lifestyle, drugs for the treatment of obesity or bariatric surgery could be considered. Clomiphene citrate is the first-line medication after weight loss that has been utilized in the past. Letrozole is supplanting clomiphene as the best option for ovulation induction for now, particularly in patients with PCOS. Metformin can improve ovulation and pregnancy rates; however, it has minimal effects in terms of raising live birth rates. Second-line therapies include gonadotropins and laparoscopic ovary drilling. In vitro fertilization can be utilized as a third-line treatment for patients with PCOS who have failed ovulation induction therapy or have other infertility factors. In summary, to achieve fertility, patients with PCOS require standardized individualized therapy.
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Tribulus terrestris saponins (TTS) have been longley used as an overall tonic and recent studies showed they influence inflammatory conditions. We examined the ameliorative effect of a commercial formula of a saponin-rich extract of TT in a model of dietary obesity in female rats focusing on their ability to control the inflammatory burden, insulin resistance (IR), adipokine expression and the related reproductive system pathologies. Female rats were fed with high fat diet (HFD) for 14 weeks to launch diet-induced obesity; they were assigned as: the obese control female rats (OFR) which received no treatment and TTS (5 and 10 mg/kg/day) treated rats; they were compared to a normal rat group. We determined the IR index, serum/tissue inflammatory cytokines, and adipose tissue adipokine expression and examined the secondary ovarian pathologies. Body weight gain, serum triglycerides and IR (>5-fold) in the OFR group were greater than the normal group; TTS lessened these parameters compared with the OFR group. TTS, at 10 mg/kg dose, ameliorated mRNA expression of leptin and visfatin genes in addition to serum inflammatory cytokine levels. Moreover, TTS corrected the hyperprolactinemia and other hormonal disturbances and ameliorated the ovarian pathologies. This study highlighted that the anti-inflammatory properties of TTS helped in alleviation of IR and body weight gain in OFR. Upon correction of obesity manifestations, the gonadal hormone dysregulations and ovarian pathologies were subsequently ameliorated. We can consider TTS as a promising candidate that may alleviate the inflammatory burden, IR and adipokine expression in obesity and hence prevent the secondary gonadal complications in female subjects if appropriate clinical studies are available.
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Background Moving from the correlation between insulin-resistance and PCOS, metformin has been administered in some PCOS women improving ovulatory and metabolic functions and decreasing androgen levels. Inconsistency and unpredictability of response to metformin limit its extensive use. Aim of this study was to identify reliable predictors of response to metformin therapy for weight loss and reduction in plasma androgen levels using ANNs (artificial neural networks). Methods One hundred eight consecutive women with PCOS (ESHRE/ASRM 2003 Rotterdam criteria) treated with metformin 1500 mg/day, at inclusion and every 6 months underwent to a complete clinical, endocrine/metabolic assessment and ultrasonographic evaluation. Therapy outcomes were BMI reduction (≥1 kg/m²) in overweight/obese and free-androgen-index (FAI) decrease (≥1%) in hyperandrogenemic women. Semantic connectivity maps (SCMs) were obtained through Auto-CM, a fourth generation ANN, to compare patients’ baseline clinical features to the treatment outcomes. Multivariate logistic regression analysis was used to assess the major predictor in drop-out patients and the associated risk. Results At 6 months 54 out of 103 (52,4%) obese patients showed BMI reduction and 45 out of 89 (50,6%) hyperandrogenemic women showed FAI decrease. The further response rates at 12 months were 30,6 and 47%, respectively. SCMs showed a clear polarization for both the outcomes with elevated accuracy. Treatment responsiveness resulted strictly related to oligo-amenorrhea and hyperandrogenemia at baseline. In addition, lower serum testosterone levels at baseline were found to be the major predictor of treatment discontinuation. Conclusions In women with PCOS, menstrual pattern imbalance and ovarian androgens excess are the best predictors of metformin response. They may pave the way for a rethinking of the criteria for evaluating hyperandrogenism in order to better define the large population included in the diagnosis of PCOS. Baseline plasma testosterone level can serve as a sensitive marker to predict treatment compliance.
Chapter
PCOS is a reproductive disorder associated with metabolic dysfunction. The beneficial effect of weight loss in ameliorating the metabolic profile of patients is well-established. Oral medications for weight loss have a modest effect. The beneficial effects of diet in managing PCOS rely on caloric restriction rather than macronutrient content. Among different diets, the Mediterranean diet, thanks to its antiinflammatory and antioxidative potential, is a well-established health promoting diet model. Exercise should be matched to dietary restrictions in order to maximize weight loss. A combination of aerobic and strength exercise of moderate (and not excessive) intensity, spread throughout the week (30–60 min/day), is the best approach to be promoted. Exercise activity should be matched to energy intake throughout 24 h in order to achieve a permanent energy equilibrium of ± 300 calories.
Article
Objective: The effect of trans-anethole and metformin on biochemical and hormonal changes of testosterone-induced Polycystic ovary syndrome (PCOS) in rats was investigated. Materials and methods: Female Wister rats (n=48) were randomly divided into six groups: control; PCOS; PCOS+metformin (300 mg/kg); and PCOS+trans-anethole (20, 40, and 80 mg/kg). PCOS was induced by intraperitoneal injection of testosterone (1 mg/kg/day) for 35 days. After induction of PCOS, trans-anethole and metformin were given orally for 30 days. Finally, blood sugar, insulin, lipid profile, and testosterone and dehydroepiandrosterone (DHEAS) as well as animals' weight, and water and food intake were determined. Results: In all treated and untreated PCOS groups, serum testosterone levels were significantly increased compared to the control group (p<0.001 for all groups). Treatment of rats with trans-anethole or metformin significantly reduced serum levels of cholesterol, insulin, triglycerides, testosterone and DHEAS (only in PCOS+trans-anethole groups) compared to the PCOS group (p<0.01-p<0.001). Weight gain in the PCOS animals increased significantly compared to the control group (p<0.001), while in the metformin- and trans-anethole (40 and 80)-treated animals it decreased significantly compared to the PCOS group (p<0.01-p<0.001). Conclusion: These results showed that trans-anethole significantly decreased serum levels of insulin, DHEAS and blood lipids. It can be concluded that trans-anethole ameliorates PCOS biochemical and hormonal change in PCOS rats; therefore, it might be suggested as a beneficial remedy for further clinical evaluations in PCOS patients.
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Objective To study the impact of a very-low carbohydrate diet for 16 weeks in overweight or obese women with polycystic ovary syndrome (PCOS). Design Single-arm prospective pilot study. Setting We recruited participants using medical records from an academic medical center. Patients Twenty-nine overweight or obese women (body mass index [BMI] 25-50 kg/m2) with PCOS. Intervention We taught participants to follow a very-low carbohydrate diet and provided information about a variety of behavioral skills including mindfulness and positive affect using an online, 16-week intervention. Main Outcome Measures Changes in body weight, glycated hemoglobin (HbA1c), and PCOS-related quality of life. Results The intervention led to positive health outcomes including decreases in percent weight (M diff. = -7.67, SD = 6.10, P <.001) and glycated hemoglobin (HbA1c; M diff. = -0.21%, SD = 0.27, P = .001), an increase in sex hormone binding globulin (SHBG; M diff. = 9.24 nmol/L, SD = 16.34, P = .01), and increases in PCOS-related quality of life measures, including menstrual predictability (M diff. = 2.10, SD = 2.76, P = .002) and body hair (M diff. = 1.14, SD = 1.04, P<.001). Low-density lipoprotein (LDL) cholesterol increased (M diff. = 0.23 mmol/L; SD = 0.49; P = .04). Conclusion Results suggest that a VLC dietary intervention has potential to promote both weight loss and glycemic control in overweight and obese adults with PCOS, two key components in the prevention of type 2 diabetes.
Chapter
Polycystic ovarian syndrome (PCOS) is a complex endocrine disorder affecting up to 10% of reproductive-age women. PCOS is characterized by three hallmark features: hyperandrogenism, oligo-/anovulation, and polycystic ovaries. Insulin resistance is also prevalent in the majority of women with PCOS, both in the lean and obese phenotypes. Other clinical manifestations of PCOS include an increased risk of obesity, type II diabetes, and cardiovascular disease. In addition to hyperandrogenism and insulin resistance, chronic inflammation is another important contributor to the pathophysiology of PCOS. The compounding effects of these features culminate in reproductive dysfunction. Due to ovarian and uterine abnormalities, women with PCOS suffer from infertility and diminished ability to carry a pregnancy to term. Ovarian aberrations include abnormal follicular development, oligoovulation/anovulation, and reduced egg quality. Uterine abnormalities include altered endometrial gene expression, increased inflammation, and decreased endometrial receptivity to implantation. This chapter reviews the mechanistic effects of hyperandrogenism, insulin resistance, and inflammation on the ovaries, uterus, and placenta, leading to reproductive dysfunction through reduced ability to ovulate, decreased endometrial receptivity, implantation failure, placental dysfunction, recurrent pregnancy loss, and various pregnancy complications including preterm birth and preeclampsia.
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Background Intake of resveratrol has been associated with improved ovarian morphology under in vitro and in the animal models; however, this finding has not been confirmed in trials. The aim of our study was, therefore, to use a placebo-controlled approach with the detailed assessment of the ovarian morphology by applying transvaginal ultrasound to examine the effectiveness of this therapeutic approach in this group of women. Methods Forty-one women with polycystic ovary syndrome (PCOS) were randomly assigned (1:1) to 3 months of daily 1000 mg resveratrol or placebo. Random assignment was done by blocked randomisation. Our primary endpoints were the change in the ovarian volume, stromal area and antral follicle count per ovary (FNPO) from the baseline to 3 months. Secondary endpoints were improvement in the distribution of follicles and ovarian echogenicity. Differences between the resveratrol and control groups were evaluated by Chi-square, fisher’s exact test and repeated-measures of ANOVA. Results The mean age of all participants was 28.61 ± 4.99 years, with the mean BMI of 28.26 ± 5.62 kg/m ² . Resveratrol therapy, as compared with placebo, was associated with a significantly higher rate of improvement in the ovarian morphology (p= 0.02). Women who received resveratrol had a more dominant follicle than those getting placebo, with a significant reduction in the ovarian volume (p<0.05). However, the number of FNPO, stromal area, ovarian echogenicity and distribution of follicles were not significantly altered (P>0.05). Conclusions Treatment with resveratrol significantly reduced the ovarian volume and PCOM, thus suggesting a disease-modifying effect in PCOS. Trial registration: IRCT, IRCT2017061917139N2. Registered 7 July 2017, http://irct.ir/trial/15836.
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Background Polycystic Ovary Syndrome (PCOS) is a complex endocrine disorder of heterogeneous nature. Secreted frizzled-related protein (SFRP) 5 is an anti-inflammatory adipokine implicated in metabolic homeostasis. We aimed to confirm the correlation between SFRP5, metabolic inflammation and PCOS, investigate the predictive value of SFRP5 for PCOS and the involvement of SFRP5 in metformin treated PCOS. Methods This retrospective case–control study included 140 PCOS and 33 control women. Sixty seven PCOS women were included for detecting serum SFRP5 level and its correlation with metabolic inflammation. Predictive value of SFRP5 for PCOS was evaluated by logistic regression and receiver operating characteristic (ROC) analyses. Seventy three PCOS women complicated with impaired glucose tolerance (IGT)/insulin resistance (IR) were included for investigating the effects of metformin (37 with metformin vs. 36 without metformin) on SFRP5, pro-inflammatory cytokines, ovulation and pregnancy rate. Results Plasma SFRP5 levels were decreased in PCOS (odds ratio: 0.78, 95% confidence interval (CI):0.703–0.866, P < 0.001) independent of obesity. SFRP5 was negatively associated with IL-6, TNFα, FAI and HOMA-IR. The cut-off point of SFRP5 < 46.13 ng/ml was optimal to identify PCOS with a higher specificity of 96.87% and a relatively lower sensitivity compared to AMH. SFRP5 increased specificity of AMH for predicting PCOS, especially which with relatively decreased AMH (< 4.7 ng/ml). Metformin promoted SFRP5 and decreased leptin, IL-6 and TNFα secretion in PCOS women with metabolic abnormality in a time dependent manner and with improved ovulation rate and pregnancy rate. Conclusion Decreased SFRP5 was associated with metabolic inflammation in PCOS and has a potential role for the supplement of AMH in predicting PCOS. The reverse of serum SFRP5 by metformin indicated that SFRP5 participated in the improvment of follicular development by metformin. Further prospective investigations are needed to confirm these preliminary data.
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Context Women with PCOS have increased incidence of atherogenic dyslipidemia and increased incidence of cardiovascular disease (CVD). Interventions to target atherogenic dyslipidemia are limited in women with PCOS to reduce CVD risk. Objective To determine the effect of high dose fish oil (FO), metformin and FO as an adjunct therapy to metformin (FO-metformin) for 12 weeks on fasting and non-fasting plasma lipids and ApoB-remnants in young women with the metabolic syndrome (MetS) and PCOS. Design, setting and participants Participants were randomized into three interventions; i) FO, ii) metformin and iii) FO-metformin in an open-label parallel pilot trial in young women aged 18-30yrs with MetS and PCOS. Main Outcome Measures Plasma lipids and ApoB (48 and 100)-lipoproteins and triglycerides (TG) were measured in the fasted and postprandial state following a high-fat meal at baseline and post-intervention. Results FO-metformin significantly lowered fasting plasma TG by >40% compared to FO and metformin treatments. Fasting plasma apoB48 was lowered 40% in FO-metformin and 15% in the FO treated groups from baseline to post-intervention. ApoB48 AUC , ApoB48 IAUC, ApoB100 AUC and ApoB100 iAUC decreased in all groups from baseline to post-intervention, however these findings did not reach statistical significance. Conclusions The findings of this pilot trial show high dose FO and FO-metformin combination therapy tend to lower fasting and post-prandial plasma TG and ApoB-lipoprotein remnants compared to metformin, however the study is limited by small sample size. These results may be clinically significant in individuals with PCOS for management of atherogenic dyslipidemia.
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Context: Insulin resistance (IR) is associated with polycystic ovaries and hyperandrogenism, but underpinning mechanisms are poorly understood, and therapeutic options limited. Objectives: A. To characterise hyperandrogenemia and ovarian pathology in primary severe IR (SIR), using IR of defined molecular etiology to interrogate disease mechanism. B. To extend evaluation of gonadotropin-releasing hormone (GnRH) analogue therapy in SIR. Design: Retrospective case note review in two SIR national referral centres. Patients: Female patients with SIR with documented serum total testosterone (TT) concentration. Results: Among 185 patients with lipodystrophy, 65 with primary insulin signaling disorders, and 29 with idiopathic SIR, serum TT ranged from undetectable to 1562 ng/dL (54.2 nmol/L; median 40.3 ng/dL (1.40 nmol/L); n=279) and free testosterone (FT) from undetectable to 18.0 ng/dL (0.625 nmol/L; median 0.705 ng/dL (0.0244 nmol/L); n=233). Higher TT but not FT in the insulin signaling subgroup was attributable to higher serum sex hormone binding globulin (SHBG) concentration. Insulin correlated positively with SHBG in the insulin signaling subgroup, but negatively in lipodystrophy. In 8/9 patients with available ovarian tissue, histology was consistent with polycystic ovary syndrome (PCOS). In 6/6 patients treated with GnRH analogue therapy, gonadotropin suppression improved hyperandrogenic symptoms and reduced serum TT irrespective of SIR etiology. Conclusions: SIR causes severe hyperandrogenemia and PCOS-like ovarian changes whether due to proximal insulin signaling or adipose development defects. A distinct relationship between IR and FT between the groups is mediated by SHBG. GnRH analogues are beneficial in a range of SIR subphenotypes.
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Background Metformin plays a consolidated role in the management of polycystic ovary syndrome (PCOS). However, there is no clear answer on how long we should treat and on how long its beneficial impact sustain after we stop treatment. We compared the effects of metformin withdrawal after long-term (LT) and short term (ST) treatment in PCOS women that had previously well responded to metformin. Methods We conducted observational longitudinal study including 44 PCOS women (31 (28–36) years and BMI 32.5 (27.7–34.9) kg/m2) that were followed for 6 months after metformin withdrawal. Prior inclusion, ST group had been treated with metformin on average for 1.03 ± 0.13 year, LT group for 5.07 ± 2.52 years. We followed anthropometric, metabolic, reproductive parameters and eating behavior as assessed by TFEQ-R18. Results After metformin withdrawal, ST group gained significant amount of weight (from 92 (75.5–107.3) kg to 96 (76–116) kg; p = 0.019). Weight tended to increase also in LT users (from 87 (75–103) to 87 (73–105) kg; p = 0.058). More women in LT group maintained stable weight (27% in LT group vs 15% in ST group). Eating behavior deteriorated in both groups. Withdrawal of metformin resulted in a decrease of menstrual frequency (6 (6–6) to 6 (4–6) menstrual bleeds per 6 months; p = 0.027) and in borderline increase of androstenedione (6.4 (4.6–7.6) to 7.8 (4.8–9.6) nmol/L; p = 0.053) in LT group. Waist circumference, HOMA and glucose homeostasis remained stable in both groups. There were no differences between groups at 6-month follow up. Conclusion Collectively, present study implies some metabolic and endocrine treatment legacy in both groups as well as some group-specific deteriorations in clinical parameters 6 months after metformin withdrawal. Trial registration: The study is registered at Clinical Trials with reference No. NCT04566718
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BACKGROUND Metabolic and endocrine alterations in women with polycystic ovary syndrome (PCOS) affect adipose tissue mass and distribution. PCOS is characterised by hyperandrogenism, obesity and adipocyte dysfunction. Hyperandrogenism in PCOS drives dysfunctional adipocyte secretion of potentially harmful adipocytokines. Glucocorticoids and sex-steroids modulate adipocyte development and function. For their part, adipocyte products interact with adrenal and ovarian steroidogenic cells. Currently, the relationship between adipocyte and steroidogenic cells is not clear, and for these reasons, it is important to elucidate the interrelationship between these cells in women with and without PCOS. OBJECTIVE AND RATIONALE This comprehensive review aims to assess current knowledge regarding the interrelationship between adipocytes and adrenal and ovarian steroidogenic cells in animal models and humans with or without PCOS. SEARCH METHODS We searched for articles published in English and Portuguese in PubMed. Keywords were as follows: polycystic ovary syndrome, steroidogenesis, adrenal glands, theca cells, granulosa cells, adipocytes, adipocytokines, obesity, enzyme activation, and cytochrome P450 enzymes. We expanded the search into the references from the retrieved articles. OUTCOMES Glucocorticoids and sex-steroids modulate adipocyte differentiation and function. Dysfunctional adipocyte products play important roles in the metabolic and endocrine pathways in animals and women with PCOS. Most adipokines participate in the regulation of the hypothalamic–pituitary–adrenal and ovarian axes. In animal models of PCOS, hyperinsulinemia and poor fertility are common; various adipokines modulate ovarian steroidogenesis, depending on the species. Women with PCOS secrete unbalanced levels of adipocyte products, characterised by higher levels of leptin and lower levels of adiponectin. Leptin expression positively correlates with body mass index, waist/hip ratio and levels of total cholesterol, triglyceride, luteinising hormone, oestradiol and androgens. Leptin inhibits the production of oestradiol and, in granulosa cells, may modulate 17-hydroxylase and aromatase enzyme activities. Adiponectin levels negatively correlate with fat mass, body mass index, waist–hip ratio, glucose, insulin and triglycerides, and decrease androgen production by altering expression of luteinising hormone receptor, steroidogenic acute regulatory protein, cholesterol-side-chain cleavage enzyme and 17-hydroxylase. Resistin expression positively correlates with body mass index and testosterone, and promotes the expression of 17-hydroxylase enzyme in theca cells. The potential benefits of adipokines in the treatment of women with PCOS require more investigation. WIDER IMPLICATIONS The current data regarding the relationship between adipocyte products and steroidogenic cells are conflicting in animals and humans. Polycystic ovary syndrome is an excellent model to investigate the interrelationship among adipocyte and steroidogenic cells. Women with PCOS manifest some pathological conditions associated with hyperandrogenism and adipocyte products. In animals, cross-talk between cells may vary according to species, and the current review suggests opportunities to test new medications to prevent or even reverse several harmful sequelae of PCOS in humans. Further studies are required to investigate the possible therapeutic application of adipokines in women with obese and non-obese PCOS. Meanwhile, when appropriate, metformin use alone, or associated with flutamide, may be considered for therapeutic purposes.
Article
Hyperthecosis is defined as the presence of nests of luteinized theca cells in the ovarian stroma. Persistent testosterone released by ovarian theca cells is unmasked postmenopausally through the loss of granulosa cell-mediated aromatization of testosterone to estradiol. Ovarian hyperthecosis (OH) usually presents with symptoms of hyperandrogenism and is often described as a severe or extreme form of Polycystic Ovary Syndrome (PCOS). Serum testosterone levels in excess of 150 ng/dl (>5.2 nmol/l) are seen in affected patients and this threshold is used to confirm a diagnosis. Treatment of hyperthecosis is multi-faceted. It addresses the attendant hyperandrogenism (hirsutism and virilization) as well as metabolic complications such as obesity and insulin resistance. Ultimately, laparoscopic bilateral salpingo-oophorectomy is definitive treatment. This remains the treatment of choice in postmenopausal women whereas treatment using GnRH agonists may be used in women of reproductive age, especially younger women. Nevertheless, if serum testosterone remains elevated despite several months of therapy with a GnRH agonist, surgery is often required for biopsy sample collection and further definitive therapy. In order to mitigate the common clinical manifestations of hyperandrogenism, anti-androgen therapy (either cyproterone acetate or spironolactone) may be used to suppress the actions of testosterone on tissues. In patients with impaired glucose metabolism and insulin resistance, Metformin should also be considered as part of treatment. Combined, such a treatment regimen will often lead to decreased ovarian androgen secretion.
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Polycystic Ovary Syndrome (PCOS) is the most common endocrine disorder in reproductive-aged women. Clinical or biochemical signs of androgen excess is a cardinal feature of the syndrome and are present in approximately 80% of women with PCOS. Increased blood pressure and insulin resistance, two major cardiovascular risk factors, are frequently present in women with PCOS. This chapter aims to highlight the fundamental role of androgens in mediating the increased blood pressure and insulin resistance in women with PCOS. This chapter is also a call for action to develop new pharmacological therapies that target the androgen synthesis and androgen receptor activation dysregulation present in women with PCOS. These novel therapies will allow to prevent or mitigate the excess androgen-mediated cardiovascular risk factors that affect women with PCOS.
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To test the hypothesis that insulin plays a role in the hyperandrogenism of obese women with polycystic ovary syndrome, we conducted a prospective study in which the androgen status of five obese women with polycystic ovary syndrome was assessed on two occasions: before and after 10 days of oral diazoxide (100 mg, three times daily) administration. Fasting serum insulin levels decreased from 177 +/- 45 (+/- SE) to 123 +/- 43 pmol/L (P less than 0.01) and insulin release in response to 100 g oral glucose administration decreased from 223.0 +/- 29.2 to 55.6 +/- 7.9 nmol.min/L (P less than 0.002) after diazoxide administration. At the same time, serum total testosterone fell from 2.5 +/- 0.4 to 2.1 +/- 0.3 nmol/L (P less than 0.007), serum testosterone not bound to sex hormone-binding globulin fell from 1.9 +/- 0.3 to 1.4 +/- 0.2 nmol/L (P less than 0.01), and the molar ratio of serum androstenedione to serum estrone fell from 25.7 +/- 7.7 to 16.6 +/- 5.5 (P less than 0.04). Serum sex hormone-binding globulin levels increased slightly but not significantly from 13.2 +/- 1.0 to 21.7 +/- 4.1 nmol/L. Serum androstenedione, dehydroepiandrosterone sulfate, estradiol, estrone, and progesterone concentrations did not change, nor did basal or GnRH-stimulated serum LH and FSH concentrations. These results suggest that hyperinsulinemia in obese women with polycystic ovary syndrome may directly increase serum testosterone levels.
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Sex hormone-binding globulin (SHBG) production in humans has been thought to be stimulated by estrogens and thyroid hormone and inhibited by androgens. However, recent data indicate that SHBG production in vitro is stimulated by both androgens and estrogens. This study was designed to determine what other hormonal factors regulate SHBG production. Since hyperinsulinemia and hyperprolactinemia both occur in disease states in which low serum SHBG levels are found, the effects of insulin and PRL were compared to and/or studied in combination with estradiol (E2), T4, and testosterone (T) in a human hepatoma cell line (Hep G2). Hep G2 cells were grown to near confluence in medium including 10% fetal calf serum, and then 72-h experimental incubations were carried out which used only fetal calf serum-free medium. Compared to control incubations, both insulin (10(-8) mol/L) and PRL (10(-8) mol/L) decreased SHBG production from 65.0 +/- 0.6 (+/- SE) to 46.8 +/- 1.1 and 46.8 +/- 1.2 nmol/10(6) cells, respectively (P less than 0.01). Insulin also inhibited both E2 and T4-stimulated SHBG production. T stimulated SHBG production to the same degree as E2. Finally, both E2 and insulin significantly increased cell number, an important consideration when expressing the effect of a hormone on SHBG production in cultured cells. We conclude that insulin and PRL inhibit SHBG production and confirm that T4, T, and E2 stimulate SHBG production in vitro. These findings suggest that insulin and PRL may be important factors in the regulation of SHBG production in vivo.
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We investigated the cellular mechanisms of the unique disorder of insulin action found in the polycystic ovary syndrome (PCOS). Approximately 50% of PCOS women (PCOS-Ser) had a significant increase in insulin-independent beta-subunit [32P]phosphate incorporation (3.7-fold, P < 0.05 vs other groups) in skin fibroblast insulin receptors that was present in serine residues while insulin-induced tyrosine phosphorylation was decreased (both P < 0.05 vs other groups). PCOS skeletal muscle insulin receptors had the same abnormal phosphorylation pattern. The remaining PCOS women (PCOS-n1) had basal and insulin-stimulated receptor autophosphorylation similar to control. Phosphorylation of the artificial substrate poly GLU4:TYR1 by the PCOS-Ser insulin receptors was significantly decreased (P < 0.05) compared to control and PCOS-n1 receptors. The factor responsible for excessive serine phosphorylation appeared to be extrinsic to the receptor since no insulin receptor gene mutations were identified, immunoprecipitation before autophosphorylation corrected the phosphorylation defect and control insulin receptors mixed with lectin eluates from affected PCOS fibroblasts displayed increased serine phosphorylation. Our findings suggest that increased insulin receptor serine phosphorylation decreases its protein tyrosine kinase activity and is one mechanism for the post-binding defect in insulin action characteristic of PCOS.
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To investigate the effects of metformin on glycemic control, insulin resistance, and risk factors for cardiovascular disease in NIDDM subjects from two ethnic groups (Caucasian and Asian) with different risks of cardiovascular disease. A total of 27 subjects with NIDDM (17 Caucasian, 10 Asian) were given metformin and placebo each for a 12-wk period in a randomized, double-blind, placebo-controlled crossover study, and the dose was increased after 1 and 6 wk, up to a maximum of 850 mg three times a day. Insulin resistance, glycemic control, and cardiovascular risk factors were assessed before and after each treatment phase. The end of 12 wk of metformin treatment was compared with the end of 12 wk of placebo treatment. Metformin treatment was associated with significant improvement in FPG at 6 and 12 wk (mean difference at 12 wk, -3.08 mM, 95% CI -4.12 to -2.04 mM, P < 0.0001) and MCR of glucose (median difference 0.40 ml.kg-1.min-1, interquartile range -0.10 to 1.30 ml.kg-1.min-1, P = 0.036). beta-cell function calculated by HOMA also improved significantly (median difference 14%, interquartile range 7 to 23%, P < 0.001). Total triglyceride (median difference -0.2 mM, interquartile range -0.6 to 0.1 mM, P = 0.034), total cholesterol (mean difference -0.52 mM, 95% CI -0.83 to -0.22 mM, P = 0.002), and LDL cholesterol (mean difference -0.40 mM, 95% CI -0.64 to -0.16 mM, P = 0.002) fell significantly on metformin treatment, whereas no significant changes were observed in HDL cholesterol. PAI-1 activity fell significantly (mean difference -5.3 AU/ml, 95% CI -8.2 to -2.4 AU/ml, P = 0.001), but plasma fibrinogen concentrations and platelet function, spontaneous or agonist induced, were unaffected. UAE was lower on metformin treatment (median difference -2.4 micrograms/min, interquartile range -4.4 to -0.2 micrograms/min, P = 0.004), but metformin had no significant effect on BP. The effects of metformin on glycemic control and cardiovascular risk factors were generally similar in the two ethnic groups. These findings indicate that metformin treatment improves glycemic control, and lowers insulin resistance and risk factors for cardiovascular disease, including PAI-1, and may therefore be useful in the long-term management of NIDDM subjects who have a high risk of cardiovascular disease.
Article
Objective: Obese women with polycystic ovary syndrome have a greater frequency of menstrual disturbance and of hirsutism than lean women with the syndrome. Initial studies have demonstrated a marked improvement in endocrine function following a short-term, very low calorie diet. The purpose of this study was to examine the effect of long-term calorie restriction on clinical as well as biochemical abnormalities in obese women with polycystic ovary syndrome. Design: We performed a within-group comparison of clinical and biochemical indices before and during dietary treatment. Patients: Twenty-four obese women with polycystic ovary syndrome (mean weight 91.5 (SD 14.7) kg) were scheduled for treatment for 6-7 months with a 1000 kcal, low fat diet. Nineteen of the 24 had menstrual disturbances, 12 had infertility and 19 were hirsute. Measurements and results: Thirteen subjects lost more than 5% of their starting weight (range 5.9-22%). In this group there was no significant change in gonadotrophin or total serum testosterone levels but there was a marked increase in concentrations of sex hormone-binding globulin (pretreatment: 23.6 (9.5); post-treatment 36.3 (11.8) nmol/l, P = 0.002) and a reciprocal change in free testosterone levels (77 (26) vs 53 (21) pmol/l, P = 0.009). These changes were accompanied by a reduction in fasting serum insulin levels (median (range) 11.2 (5.2-32) vs 2.3 (0.1-13.8) mU/l, P = 0.018) and the insulin response to 75 g oral glucose. There were no significant changes in these indices in the group who lost less than 5% of their initial body weight. Of the 13 women who lost greater than 5% of their pretreatment weight, 11 had menstrual dysfunction. Amongst these women, nine of 11 showed an improvement in reproductive function, i.e. they either conceived (five) or experienced a more regular menstrual pattern. There was a reduction in hirsutism in 40% of the women in this group. By contrast, in the group who lost less than 5% of their initial weight, only one of the eight with menstrual disturbances noted an improvement in reproductive function and none had a significant reduction in hirsutism. Conclusions: These data indicate that moderate weight loss during long-term calorie restriction is associated with a marked clinical improvement which reflects the reduction in insulin concentrations and reciprocal changes in SHBG. The improvement in menstrual function and fertility may therefore be consequent upon an increase in insulin sensitivity which, directly or indirectly, affects ovarian function.
Article
Using polycystic ovary syndrome (PCOS) as a model of insulin resistance and hyperandrogenism, our specific aim was to assess the effect of Metformin on lipoproteins, sex hormones, gonadotropins, and blood pressure in 26 women with PCOS who were studied at baseline, received Metformin 1.5 g/d for 8 weeks, and were then restudied. None of the women had normal menstrual cycles, 100% had multiple subcapsular follicules by pelvic ultrasound, 90% were hirsute, and 85% had high free testosterone. Comparing post-Metformin versus baseline levels, the Quetelet Index (QI) decreased 1.5% (P = .04) and the waist to hip ratio (WHR) decreased 2.8% (P = .003). After covariance adjusting for changes in the QI and WHR, on Metformin the area under the insulin curve (IA) during oral glucose tolerance testing decreased 35% (P = .04), and the insulin area to glucose area ratio decreased 31% (P = .03). On Metformin, covariance-adjusted systolic blood pressure (SBP) decreased (P = .04) and apo A-1 increased (P = .05). On Metformin, with improvement in insulin sensitivity, there were sharp reductions in covariance-adjusted luteinizing hormone ([LH] P = .0007), total testosterone ([T] P = .0004), free T (P = .0001), androstenedione (P = .002), dehydroepiandrosterone sulfate ([DHEAS] P = .006), and the free androgen index ([FAI] P = .0005), with increments in follicle-stimulating hormone ([FSH] P = .04) and sex hormone-binding globulin ([SHBG] P = .04).(ABSTRACT TRUNCATED AT 250 WORDS)
Article
Distinguishing between ovarian and adrenal causes of androgen excess may be difficult. We have found that women with the polycystic ovary syndrome have supranormal plasma 17-hydroxyprogesterone responses to the gonadotropin-releasing hormone agonist nafarelin. We determined the usefulness of testing with nafarelin to distinguish ovarian causes of hyperandrogenism in women. We studied 40 consecutive women with hyperandrogenism who had oligomenorrhea, hirsutism, or acne. All 40 underwent testing with nafarelin, dexamethasone, and corticotropin with measurement of circulating concentrations of gonadotropins and steroid hormones, and 19 underwent ovarian ultrasonography. The plasma 17-hydroxyprogesterone response to nafarelin was supranormal in 23 of the 40 women (58 percent), and the plasma androgen response to corticotropin was elevated in 23; 13 women had both abnormalities. Only one woman had conclusive evidence of a steroidogenic block; she had nonclassic adrenal 21-hydroxylase deficiency. Of the 23 women with abnormal responses to nafarelin, only 11 (48 percent) had elevated base-line serum luteinizing hormone concentrations. Of the 13 women with abnormal responses to nafarelin who underwent ultrasonography, 7 (54 percent) had polycystic ovaries. Peak plasma 17-hydroxyprogesterone concentrations after nafarelin administration correlated closely with plasma free testosterone concentrations after dexamethasone administration (r = 0.75, P less than 0.001). Approximately half of women with oligomenorrhea, hirsutism, or acne have an abnormal response to the gonadotropin-releasing hormone agonist nafarelin, suggesting an ovarian cause of their androgen excess.
Article
Insulin resistance is a predominant feature in women with polycystic ovarian syndrome (PCO). The cellular mechanisms for this insulin resistance have not been defined. In this study, major steps in the insulin action cascade, receptor binding, kinase activity, and glucose transport activity were evaluated in isolated adipocytes prepared from PCO subjects (n = 8) without acanthosis nigricans and in a group of age and weight-matched controls [normal cycling (NC) n = 8]. The PCO group was hyperinsulinemic and displayed elevated insulin responses to an iv glucose load. The binding of 125I-insulin to adipocytes was similar in cells from PCO and NC subjects. In PCO, autophosphorylation of the insulin receptor-subunit in the absence of insulin was normal but a significant decrease (30% below control) in maximal insulin stimulated autophosphorylation was observed. However, receptor kinase activity measured against the exogenous substrate poly glu:tyr (4:1) was normal. Cells from PCO subjects transported glucose at the same rate, in both the absence and presence of a maximal insulin concentration, as those from NC subjects. Strikingly, there was a large rightward shift in the insulin dose-response curve for transport stimulation in PCO cells (EC50 = 87 +/- 14 pmol in NC vs. 757 +/- 138 in PCO, P less than 0.0005); 8-fold greater insulin concentrations were required to attain comparable glucose transport rates in cells from PCO against NC. In conclusion, our results suggest that insulin resistance in PCO, as assessed in the adipocyte, is accompanied by normal function of insulin receptors, but involves a novel postreceptor defect in the insulin signal transduction chain between the receptor kinase and glucose transport.
Article
Our purpose was to determine the prevalence of adrenal hyperandrogenism and insulin resistance in patients with hyperandrogenic chronic anovulation, also called polycystic ovary syndrome, living in the United States, Italy, and Japan. Seventy-five women with polycystic ovary syndrome, 25 each from the United States, Italy, and Japan, and 10 ovulatory controls were studied. Hirsutism, obesity, and the presence of cystic ovaries were assessed, as were blood levels for estrogen, luteinizing hormone, testosterone, adrenal androgens, and insulin. All patients received an insulin tolerance test to assess insulin resistance. Women from Japan were less obese (p < 0.05) and did not have hirsutism, although the percentage of cystic ovaries (68% to 80%) was comparable. Serum luteinizing hormone, testosterone, and estradiol were similar, but levels of 3 alpha-androstanediol glucuronide, which was elevated in women from the United States and Italy, was normal in women from Japan. The adrenal androgens, dehydroepiandrosterone sulfate and 11 beta-hydroxyandrostenedione were elevated in 48% to 64% of the patients and by a similar percentage in the three groups. Fasting insulin was elevated in all groups, but was significantly higher in women from the United States and Italy compared with women from Japan (p < 0.05). However, insulin resistance as assessed by dissociation constant of insulin tolerance test values was significantly elevated but similar in the three groups and occurred in 68% to 76% of patients. In polycystic ovary syndrome, although obesity and hirsutism vary according to dietary, genetic, and environmental factors, the prevalence of adrenal androgen excess and insulin resistance appear to be fairly uniform. These results suggest that these factors may be involved in the pathophysiologic features of the disorder.
Article
Obese women with polycystic ovary syndrome have a greater frequency of menstrual disturbance and of hirsutism than lean women with the syndrome. Initial studies have demonstrated a marked improvement in endocrine function following a short-term, very low calorie diet. The purpose of this study was to examine the effect of long-term calorie restriction on clinical as well as biochemical abnormalities in obese women with polycystic ovary syndrome. We performed a within-group comparison of clinical and biochemical indices before and during dietary treatment. Twenty-four obese women with polycystic ovary syndrome (mean weight 91.5 (SD 14.7) kg) were scheduled for treatment for 6-7 months with a 1000 kcal, low fat diet. Nineteen of the 24 had menstrual disturbances, 12 had infertility and 19 were hirsute. Thirteen subjects lost more than 5% of their starting weight (range 5.9-22%). In this group there was no significant change in gonadotrophin or total serum testosterone levels but there was a marked increase in concentrations of sex hormone-binding globulin (pretreatment: 23.6 (9.5); post-treatment 36.3 (11.8) nmol/l, P = 0.002) and a reciprocal change in free testosterone levels (77 (26) vs 53 (21) pmol/l, P = 0.009). These changes were accompanied by a reduction in fasting serum insulin levels (median (range) 11.2 (5.2-32) vs 2.3 (0.1-13.8) mU/l, P = 0.018) and the insulin response to 75 g oral glucose. There were no significant changes in these indices in the group who lost less than 5% of their initial body weight. Of the 13 women who lost greater than 5% of their pretreatment weight, 11 had menstrual dysfunction. Amongst these women, nine of 11 showed an improvement in reproductive function, i.e. they either conceived (five) or experienced a more regular menstrual pattern. There was a reduction in hirsutism in 40% of the women in this group. By contrast, in the group who lost less than 5% of their initial weight, only one of the eight with menstrual disturbances noted an improvement in reproductive function and none had a significant reduction in hirsutism. These data indicate that moderate weight loss during long-term calorie restriction is associated with a marked clinical improvement which reflects the reduction in insulin concentrations and reciprocal changes in SHBG. The improvement in menstrual function and fertility may therefore be consequent upon an increase in insulin sensitivity which, directly or indirectly, affects ovarian function.
Article
The effect of metformin on glucose metabolism was examined in eight obese (percent ideal body weight, 151 +/- 9%) and six lean (percent ideal body weight, 104 +/- 4%) noninsulin-dependent diabetic (NIDD) subjects before and after 3 months of metformin treatment (2.5 g/day). Fasting plasma glucose (11.5-8.8 mmol/L), hemoglobin-A1c (9.8-7.7%), oral glucose tolerance test response (20.0-17.0 mmol/L; peak glucose), total cholesterol (5.67-4.71 mmol/L), and triglycerides (2.77-1.52 mmol/L) uniformly decreased (P less than 0.05-0.001) after metformin treatment; fasting plasma lactate increased slightly from baseline (1.4 to 1.7 mmol/L; P = NS). Body weight decreased by 5 kg in obese NIDD subjects, but remained constant in lean NIDD. Basal hepatic glucose production declined in all diabetics from 83 to 61 mg/m2.min (P less than 0.01), and the decrease correlated (r = 0.80; P less than 0.01) closely with the fall in fasting glucose concentration. Fasting insulin (115 to 79 pmol/L) declined (P less than 0.05) after metformin. During a 6.9 mmol/L hyperglycemic clamp, glucose uptake increased in every NIDD subject (113 +/- 15 to 141 +/- 12 mg/m2.min; P less than 0.001) without a change in the plasma insulin response. During a euglycemic insulin clamp, total glucose uptake rose in obese NIDD subjects (121 +/- 10 to 146 +/- 9 mmol/m2.min; P less than 0.05), but decreased slightly in lean NIDD (121 +/- 10 to 146 +/- 0.5; P = NS). Hepatic glucose production was suppressed by more than 80-90% in all insulin clamp studies before and after metformin treatment. In conclusion, metformin lowers the fasting plasma glucose and insulin concentrations, improves oral glucose tolerance, and decreases plasma lipid levels independent of changes in body weight. The improvement in fasting glucose results from a reduction in basal hepatic glucose production. Metformin per se does not enhance tissue sensitivity to insulin in NIDD subjects. The improvement in glucose metabolism under hyperglycemic, but not euglycemic, conditions suggests that metformin augments glucose-mediated glucose uptake. Metformin has no stimulatory effect on insulin secretion.
Article
Women with the polycystic ovary syndrome (PCO) have significant insulin resistance and are at risk to develop noninsulin-dependent diabetes mellitus. It remains controversial, however, whether hyperandrogenism directly decreases insulin action. Hence, we performed 2-h euglycemic glucose (approximately 772 pmol/L steady state insulin levels) clamps in nine PCO women with insulin resistance basally and after the 12th week of therapy with a superagonist GnRH analog (40 micrograms every 8 h, sc). Diet, activity, and weight were kept constant. Despite significant decreases in plasma testosterone and androstenedione levels (both P less than 0.05), there was no significant change in insulin-mediated glucose disposal, plasma insulin levels, or hepatic glucose production. The sample size was adequate to detect a clinically significant change in insulin-stimulated glucose disposal (i.e. approximately 3.3 mumol/kg.min; P less than or equal to 0.05). We conclude that suppressing androgen levels into the normal range did not result in significant changes in insulin resistance in PCO. Thus, controlling hyperandrogenemia is not a clinically effective modality to improve insulin action and thereby decrease the risk of noninsulin-dependent diabetes in PCO.
Article
Polycystic ovarian disease (PCOD) is associated with elevated serum LH and (sub)normal FSH levels, while serum androgen levels are often elevated. To clarify the role of androgens in this abnormal pattern of gonadotropin secretion, LH secretion was studied in 1) 9 eugonadal female to male transsexual subjects before and during long term (6 months) testosterone (T) administration (250 mg/2 weeks, im), and 2) in a woman with an androgen-secreting ovarian tumor both before and after surgical removal of the tumor. Finally, we studied the effects of high serum androgen levels on ovarian histology in 3) 26 transsexual subjects after long term (9-36 months) T administration (250 mg/2 weeks, im) to assess whether T-induced ovarian abnormalities are similar to those that occur in women with PCOD. Long term T treatment in the nine female to male transsexual subjects resulted in increases in the mean serum T level from 1.7 +/- 0.8 (+/- SD) to 40.8 +/- 31.9 nmol/L (P less than 0.01), the mean serum dihydrotestosterone level from 0.6 +/- 0.2 to 3.3 +/- 1.5 nmol/L (P less than 0.02), and the mean serum free T level from 9.5 +/- 5.2 to 149 +/- 46 pmol/L (P less than 0.02). Mean serum estrone and estradiol levels were similar before and during T treatment. The mean serum LH level decreased from 6.3 +/- 2.0 to 2.9 +/- 1.1 U/L (P less than 0.01), and the mean FSH levels decreased from 6.6 +/- 2.0 to 3.7 +/- 2.2 U/L (P less than 0.02). Pulsatile LH secretion before and during T treatment was studied in five subjects. Neither the mean nadir LH interval nor the LH pulse amplitude changed significantly in these five subjects. The serum T level in the woman with the androgen-secreting ovarian tumor was 9.6 nmol/L, and it declined to normal after removal of the tumor. Her mean serum LH and FSH levels, the mean nadir LH interval, and LH pulse amplitude were in the normal range before and after removal of the tumor. Studies of ovarian histopathology in 26 transsexual subjects after long term androgen treatment revealed multiple cystic follicles in 18 subjects (69.2%), diffuse ovarian stromal hyperplasia in 21 subjects (80.8%), collagenization of the tunica albuginea in 25 subjects (96.2%), and luteinization of stromal cells in 7 subjects (26.9%). Findings consistent with criteria for the pathological diagnosis of polycystic ovaries, that is 3 of the 4 findings listed above, were present in 18 of the 26 subjects (69.2%).(ABSTRACT TRUNCATED AT 400 WORDS)
Article
Hyperinsulinemia secondary to a poorly characterized disorder of insulin action is a feature of the polycystic ovary syndrome (PCO). However, controversy exists as to whether insulin resistance results from PCO or the obesity that is frequently associated with it. Thus, we determined in vivo insulin action on peripheral glucose utilization (M) and hepatic glucose production (HGP) with the euglycemic glucose-clamp technique in obese (n = 19) and nonobese (n = 10) PCO women and age- and body-composition-matched normal ovulatory women (n = 11 obese and n = 8 nonobese women). None had fasting hyperglycemia. Two obese PCO women had diabetes mellitus, established with an oral glucose tolerance test; no other women had impairment of glucose tolerance. However, the obese PCO women had significantly increased fasting and 2-h glucose levels after an oral glucose load and increased basal HGP compared with their body-composition-matched control group. There were statistically significant interactions between obesity and PCO in fasting glucose levels and basal HGP (P < .05). Steady-state insulin levels of ~100 μU/ml were achieved during the clamp. Insulin-stimulated glucose utilization was significantly decreased in both PCO groups whether expressed per kilogram total weight (P < .001) or per kilogram fat free mass (P < .001) or when divided by the steady-state plasma insulin (I) level (M/I, P < .001). There was residual HGP in 4 of 15 obese PCO, 0 of 11 obese normal, 2 of 10 nonobese PCO, and 0 of 8 nonobese normal women. The metabolic clearance rate of insulin did not differ in the four groups. We conclude that 1) PCO women have significant insulin resistance that is independent of obesity, changes in body composition, and impairment of glucose tolerance, 2) PCO and obesity have a synergistic deleterious effect on glucose tolerance, 3) hyperinsulinemia in PCO is not the result of decreased insulin clearance, and 4) PCO is associated with a unique disorder of insulin action.
Article
The purpose of this study was to investigate the effect of calorie restriction on serum concentrations of sex hormone binding globulin (SHBG) in women with normal or polycystic ovaries (PCO) and to examine the possible role of insulin and insulin-like growth factor-I (IGF-I) in mediating changes in SHBG levels. Six normal subjects with mean (SD) body mass index (BMI) 25.5 (2.2) and five subjects with PCO (BMI 36.1 (3.7)) were studied before and after 2 or (PCO only) 4 weeks of a very low calorie diet (330 kcal/day; Cambridge Diet). In both normal women and patients with PCO there was a twofold increase in SHBG concentrations after 2 weeks and this was sustained in the PCO subjects for a further 2 weeks. The rise in SHBG was accompanied by a fall in free testosterone concentrations. There were parallel changes in serum insulin and IGF-I concentrations which decreased during the diet and there were significant negative correlations of SHBG with insulin in both normal subjects (r = -0.62) and women with PCO (r = -0.60). In addition, serum concentrations of an insulin-dependent small molecular weight (34 kDa) binding protein for IGF-I (IGF-BPI) increased significantly during dieting in both groups and were negatively correlated with serum insulin (controls, r = -0.56; PCO, r = -0.68) and positively correlated with serum SHBG levels (controls, r = 0.69; PCO, r = 0.63). In summary, these data indicate that in both normal subjects and those subjects with PCO, calorie restriction results in a highly significant increase in SHBG concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
We tested the hypothesis that insulin-like growth factor I (IGF-I) and insulin play a role in androgen production by rat ovarian thecal-interstitial cells. Collagenase/DNase-dispersed rat ovarian thecal-interstitial cells obtained from immature hypophysectomized Sprague-Dawley rats were cultured at a concentration of 10(6) cells/ml in serum-free medium in the presence of increasing concentrations of LH, IGF-I, or insulin. The medium was replaced every 48 h, and the androsterone concentration in the culture supernatants was used as an index of androgen production. In the absence of added hormones (control) androsterone levels were consistently less than 0.1 ng/ml. Increasing concentrations of LH stimulated androsterone synthesis in a dose-dependent manner. IGF-I, in the absence of LH, did not significantly increase androsterone levels above control values. However, when combined with 10 ng/ml LH, IGF-I increased androsterone synthesis above levels seen with LH alone in a dose-related fashion: for example, the peak androsterone levels seen with LH and 100 ng/ml (13 nM) IGF-I at 96 h of culture were significantly greater than the peak level seen with 10 ng/ml LH alone (302 +/- 71 vs. 17 +/- 7 ng/ml; P less than 0.0125). Similarly, while insulin alone did not increase androsterone synthesis above control values, androsterone concentrations were increased by insulin in combination with 10 ng/ml LH; a peak value of 240 +/- 67.7 ng/ml was observed at 96 h of culture with 100 ng/ml (18 mM) insulin (P less than 0.025 vs. LH alone) Androsterone levels were slightly less with insulin than with IGF-I, but this difference was not significant. The combination of IGF-I and insulin did not increase levels of androsterone synthesis above those observed with each hormone alone. IGF-I bound to a high affinity binding site on ovarian cell monolayer cultures with an apparent binding affinity of 1.3 x 10(-9) M. Insulin also competed for binding with radiolabeled IGF-I in a dose-dependent manner, but the affinity of insulin was approximately 500-fold less; half-maximal inhibition of [125I] IGF-I binding occurred with an insulin concentration of approximately 300 nM (or approximately 1700 ng/ml). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of thecal-interstitial cell monolayers affinity labeled with radiolabeled IGF-I in the absence and presence of unlabeled hormone revealed proteins with characteristics of type I IGF receptors. Affinity labeling to a protein of a relative molecular mass of approximately 45,000 was also noted, probably representing IGF carrier proteins synthesized by thecal-interstitial cell monolayers.(ABSTRACT TRUNCATED AT 400 WORDS)
Article
This study was designed to investigate whether androgens directly, independent of their aromatization to estrogens, disrupt gonadotropin secretion in hyperandrogenic women with the polycystic ovary syndrome (PCO). Pulsatile gonadotropin release and gonadotroph sensitivity to GnRH were determined on consecutive study days basally and during a primed continuous infusion of testosterone (T; n = 4; 100 micrograms/h; twice the mean production rate of T in PCO) or dihydrotestosterone (DHT; n = 5; 50 micrograms/h). To determine if the gonadotropin secretory changes during T infusion were secondary to spontaneous variation, four patients had two consecutive basal studies, and all patients received DHT on the third study day. T infusion that increased mean plasma T levels from 76 +/- 12 (+/- SE) to 315 +/- 28 ng/dl produced no significant changes in the amount or pattern of LH release or in LH sensitivity to GnRH. Mean plasma FSH levels decreased slightly but significantly during T infusion (basal, 242 +/- 29 vs. T 226 +/- 30 ng/ml LER-907; P less than 0.05 by two-tailed paired t test), but the pulsatile pattern of FSH release and FSH sensitivity to GnRH did not change. DHT infusion increased plasma DHT levels from 17 +/- 3 to 244 +/- 31 ng/dl, but did not alter the mean levels, pulsatile patterns, or sensitivity to GnRH of LH or FSH. These data suggest that androgens do not directly alter gonadotropin release in PCO. Thus, regulation of the hypothalamic-pituitary axis in women with PCO is different from that in men despite chronic exposure to hyperandrogenemia.
Article
Pituitary reactivity to GnRH, characteristic of polycystic ovarian disease (PCOD), has been attributed both to a primary ovarian cause and to hypothalamic-pituitary dysfunction. If the heightened pituitary reactivity characteristic of PCOD patients is secondary to chronic anovulation, ovulatory cycles should produce changes in the LH to FSH ratio and reduce the augmented response to GnRH. In a randomized cross-over study of 10 women with PCOD, GnRH (100 micrograms) was injected iv on the fifth day of 2 consecutive cycles, 1 of them following anovulation and progesterone withdrawal bleeding and the other following an induced ovulatory cycle. Mean basal plasma 17 beta-estradiol, progesterone, and FSH levels were similar after ovulatory and anovulatory cycles. However, mean basal serum testosterone (P less than 0.05) and LH (P less than 0.01) levels were significantly lower, as were LH levels 30, 60, and 90 min (P less than 0.01) and FSH levels 60 and 90 min (P less than 0.05) after GnRH injection, after an ovulatory cycle than after an anovulatory cycle. The pituitary response to GnRH in those PCOD patients, therefore, was more normal after an ovulatory cycle than after an anovulatory cycle. We conclude that the heightened pituitary reactivity characteristic of PCOD patients is associated with chronic anovulation.
Article
The effects of insulin and insulin-like growth factors (IGFs) on ovarian androgen production were examined in ovarian stroma obtained from four women with hyperandrogenism and three women without hyperandrogenism. In incubations of stroma obtained from all four hyperandrogenic patients, insulin alone (500 ng/ml) significantly stimulated androstenedione and testosterone release. LH alone (25 ng/ml) significantly stimulated androstenedione release in incubations of stroma obtained from three of the four hyperandrogenic patients and testosterone release in incubations of stroma obtained from one of the four hyperandrogenic patients. In stromal incubations from three of the four hyperandrogenic patients, insulin alone (500 ng/ml) resulted in a significantly greater release of androstenedione and testosterone than did LH alone (25 ng/ml). Dihydrotestosterone was released in measurable quantities in incubations of stromal tissue obtained from three of the four hyperandrogenic women. In all three instances in which dihydrotestosterone was detectable, insulin alone (500 ng/ml), but not LH alone (25 ng/ml), significantly stimulated dihydrostestosterone release. Incubations of stroma obtained from three nonhyperandrogenic, normally cycling women demonstrated low levels of androstenedione release and negligible testosterone and dihydrotestosterone release. Insulin alone (500 ng/ml) and LH alone (25 ng/ml) produced no significant increase in androstenedione release. Insulin (500 ng/ml) plus LH (25 ng/ml) significantly stimulated androstenedione accumulation in stroma obtained from two of the nonhyperandrogenic women. One insulin dose-response experiment was performed using stromal tissue obtained from a hyperandrogenic woman. In this experiment, insulin, at a dose of 50 ng/ml, was as effective as insulin at a dose of 500 ng/ml in stimulating androstenedione and testosterone release. In addition to insulin, IGF-I/somatomedin C (50 ng/ml) stimulated androstenedione and testosterone release. Relaxin (1 microgram/ml) and multiplication-stimulating activity (50 ng/ml) did not stimulate androstenedione and testosterone release. These studies suggest that human ovarian stroma may be a target tissue for insulin and IGF-I, and that hyperinsulinemia may be an important factor contributing to ovarian hyperandrogenism.
Article
Ultrasonographic (US) study was performed in 25 healthy women and 104 patients with polycystic ovarian disease (PCOD). Although the average size of ovaries in the PCOD patients was much larger than that of the healthy women, 29.7% of ovaries in the PCOD patients were normal in size. The shapes of the ovaries (roundness index) in PCOD patients were not different from those of the healthy women. There was no significant correlation between the size and shape of the ovaries. Bilaterally enlarged, globular-shaped ovaries were rare and usually asymmetric in size. The most important feature of PCOD on US scans is the bilaterally increased numbers of developing follicles (0.5-0.8 cm in size), usually more than five in each ovary. Although maturing follicles (1.5-2.9 cm) are much rarer in PCOD patients (13.5%) than in healthy women (36%), the incidences of follicular cysts (greater than 3 cm) was about the same in both.
Article
To determine whether insulin resistance occurs in polycystic ovarian disease (PCO) in the absence of obesity and acanthosis nigricans, circulating levels of insulin in response to oral glucose administration were measured in 10 nonobese PCO patients without acanthosis nigricans and in 10 normal women matched for weight and height. Mean serum testosterone (T), androstenedione (A), dehydroepiandrosterone (D), D sulfate, and LH levels were significantly elevated in the PCO patients compared to those in control subjects. In PCO patients, the mean +/- SE basal insulin level (18.7 +/- 2.9 microU/ml) and the sum of the insulin levels in response to glucose (674 +/- 119 microU/ml) were significantly greater than those in the control group (11.0 +/- 0.8 microU/ml and 248 +/- 29 microU/ml, respectively). In all subjects, serum levels of T and A, but not D and D sulfate, were significantly correlated to basal insulin levels and insulin sums. Serum cortisol, GH, and PRL levels were similar in both groups. These results indicate that in PCO, a significant degree of insulin resistance exists, which clearly is not related to obesity. The positive correlation of serum T and A levels to circulating insulin levels in this study suggests that the insulin resistance in PCO may be, in part, a consequence of hyperandrogenism.
Article
The role of insulin in the regulation of basal and gonadotropin-releasing hormone (GnRH)-stimulated release of LH and FSH was investigated in vitro using primary cultures of rat anterior pituitary cells from adult ovariectomized rats. Anterior pituitary cells were incubated for 2 days in the presence or absence of insulin in a serum-free medium. At the end of the insulin treatment, the cells were washed and reincubated in the presence or absence of GnRH, and the LH and FSH released into the medium were measured by RIA. Treatment with insulin (1.0 microgram/ml) for 2 days resulted in significant increases in both the basal and the maximal release of LH and FSH, as well as a 3.2- and 6.3-fold decrease in the ED50 values for GnRH in terms of LH and FSH release, respectively. Treatment with increasing concentrations (0.1-10,000 ng/ml) of insulin, led to a dose-dependent increase in the GnRH (3 X 10(-10) M)-stimulated release of both LH and FSH. This effect of insulin was significant (P less than 0.05) at a physiological concentration of 1 ng/ml (24 microU/ml) with an ED50 value of 40 ng/ml. Increasing duration of exposure to insulin resulted in time-dependent increases in the GnRH (3 X 10(-10) M)-stimulated release of LH, becoming significant at 24 h with maximal enhancement observed by 48 h. The effect of insulin was specific; epidermal or fibroblast growth factor did not enhance LH release. The augmenting effect of insulin was not associated with cellular proliferation or an overall change in protein or LH synthesis. Furthermore, the effect of insulin was independent of the ambient glucose concentration. Insulin was, however, without effect on gonadotrophs cultured in a serum-supplemented medium. Our findings suggest that the gonadotroph constitutes a target cell of insulin and that insulin may act directly on the anterior pituitary in the regulation of gonadotropin release.
Article
Recently, we reported that hyperandrogenism in adolescent girls is accompanied by augmented LH pulsatility and elevated LH/FSH ratio with increased ovarian volume. Together with higher concentrations of 17-hydroxyprogesterone, androstenedione, testosterone, and estrone that are ovarian in origin, these neuroendocrine features are identical to those seen in adult women with polycystic ovary syndrome. In the present study, we report the metabolic characteristics of these hyperandrogenic adolescent girls. The GH insulin-like growth factor I (IGF-I)-binding protein (BP)-3 axis, insulin sensitivity, and insulin-IGFBP-1/insulin sex hormone binding globulin axes were evaluated in 13 adolescent girls (ages 11-18 yr) with mild to moderate signs of hyperandrogenism (HA) and 28 age-matched normal girls. Insulin sensitivity was assessed by a frequent-sample iv glucose tolerance test (ivGTT, 0.3 g/kg). Twenty-four hour blood samples were obtained at 10-min intervals and were used to determine GH pulsatility (20-min samples), IGFBP-3 levels (0800-0900 h), and fluctuations of insulin, IGFBP-1, and IGF-I (hourly samples) during feeding and fasting phases of the day. In addition, GH responses to GHRH stimulation (1 microgram/kg) were assessed. Fasting insulin concentrations, but not plasma glucose levels, were significantly elevated in the HA group compared with those in the normal group (256 +/- 35 vs. 103 +/- 24 pmol/L, P = 0.0008), as were insulin responses to ivGTT and meals (P < 0.01) and 24-h mean insulin concentrations (P < 0.01). Thus, hyperinsulinemia with normal fasting glucose levels in HA girls may reflect insulin resistance, as suggested by the increased ratio of insulin and glucose (P < 0.001). All measures of insulin were correlated with body mass index (BMI); however, insulin remained significantly higher in the HA group after correcting for BMI, suggesting that decreased insulin sensitivity was related to other factors in addition to BMI. Twenty-four hour IGFBP-1 concentrations showed a diurnal pattern with an inverse relationship to insulin, and 24-h mean concentrations were lower in the HA group (0.35 +/- 0.13 vs. 0.76 +/- 0.09 micrograms/L, P = 0.02). Reduced sex hormone binding globulin levels were also inversely related to insulin levels (P = 0.0007). In contrast, GH pulsatile characteristics and IGF-I/IGFBP-3 levels, as well as GH responses to GHRH, were similar between the groups.(ABSTRACT TRUNCATED AT 400 WORDS)
Article
Evidence suggests that hyperinsulinemic insulin resistance may increase serum levels of ovarian androgens and reduce sex hormone-binding globulin (SHBG) levels in humans. The present study was conducted to assess the effect of administration of the biguanide metformin, a drug commonly used in the treatment of diabetes mellitus, on androgen and insulin levels in 24 hirsute patients. The patients selected for the study were obese, with a body mass index higher than 25 kg/m2 and high fasting insulin (> 90 pmol/L) and low SHBG levels (< 30 nmol/L). All patients were given a low calorie diet (1500 Cal/day) and randomized for either metformin administration at a dose of 850 mg or a placebo, twice daily for 4 months, in a double blind study. In the placebo group, diet resulted in a significant decrease in body mass index (30.8 +/- 1.0 vs. 32.7 +/- 1.5 kg/m2; P < 0.0001), fasting insulin (127 +/- 11 vs. 156 +/- 14 pmol/L; P < 0.01), non-SHBG-bound testosterone (0.19 +/- 0.02 vs. 0.28 +/- 0.03 nmol/L; P < 0.02), androstenedione (5.8 +/- 0.5 vs. 9.0 +/- 1.1 nmol/L; P < 0.03), and 3 alpha-diolglucuronide (8.6 +/- 1.1 vs. 11.7 +/- 1.9; P < 0.005) plasma concentrations and a significant increase in the glucose/insulin ratio (0.047 +/- 0.005 vs. 0.035 +/- 0.003; P < 0.001) and plasma concentrations of SHBG (26.0 +/- 3.3 vs. 19.1 +/- 1.9 nmol/L; P < 0.001) and dehydroepiandrosterone sulfate (8.7 +/- 1.5 vs. 8.4 +/- 1.3; P < 0.05). Beneficial effects of diet were not significantly different in the patients who were given metformin instead of placebo. These results confirm that weight loss induced by a low calorie diet is effective in improving hyperinsulinemia and hyperandrogenism in obese and hirsute women. With our study design, metformin administration had no additional benefit over the effect of diet.
Article
The increased prevalence of non-insulin-dependent diabetes mellitus (NIDDM) among women with polycystic ovary syndrome (PCOS) has been ascribed to the insulin resistance characteristic of PCOS. This study was undertaken to determine the role of defects in insulin secretion as well as familial factors to the predisposition to NIDDM seen in PCOS. We studied three groups of women: PCOS with a family history of NIDDM (PCOS FHx POS; n = 11), PCOS without a family history of NIDDM (PCOS FHx NEG; n = 13), and women without PCOS who have a family history of NIDDM (NON-PCOS FHx POS; n = 8). Beta cell function was evaluated during a frequently sampled intravenous glucose tolerance test, by a low dose graded glucose infusion, and by the ability of the beta cell to be entrained by an oscillatory glucose infusion. PCOS FHx POS women were significantly less likely to demonstrate appropriate beta cell compensation for the degree of insulin resistance. The ability of the beta cell to entrain, as judged by the spectral power for insulin secretion rate, was significantly reduced in PCOS FHx POS subjects. In conclusion, a history of NIDDM in a first-degree relative appears to define a subset of PCOS subjects with a greater prevalence of insulin secretory defects. The risk of developing NIDDM imparted by insulin resistance in PCOS may be enhanced by these defects in insulin secretion.
Article
A previously published study has identified that anovulatory women with PCOS have an increased response of 17 alpha-hydroxyprogesterone (17OHP) and androstenedione to a GnRH analogue suggesting dysregulation of cytochrome P450c17 alpha. The object of this study was to compare the responses of the pituitary-ovarian axis to a single dose of a long-acting GnRH agonist (GnRHa) in both ovulatory and anovulatory women with PCOS with those in normal subjects. Comparative study of responses of LH, FSH and ovarian steroids to buserelin and the adrenal steroid response to synthetic ACTH in two groups of women with hyperandrogenaemia and polycystic ovaries: those with anovulatory menses or amenorrhoea and those with equally elevated serum testosterone concentrations but regular menses. Results in both groups of women with PCO were compared with those in normal subjects. Twenty-four women with hyperandrogenism and PCO (14 had oligo or amenorrhoea, 10 regular cycles) and 12 weight matched controls with normal ovaries, regular cycles and neither clinical nor biochemical evidence of hyperandrogenism. Subjects were given synthetic ACTH (Synacthen) 250 micrograms i.v. on day 1 of the study and blood collected at 30 and 60 minutes thereafter. On the evening of day 1, dexamethasone treatment was commenced to suppress adrenal androgens. GnRHa 100 micrograms s.c. was given on day 2 and blood samples collected at 30-minute intervals for 4 hours and once more at 24 hours after the injection. The acute responses of both immunoactive and bioactive LH to GnRHa were significantly greater in the ovulatory PCO group (ovPCO) than controls but the response was greater in anovulatory women with polycystic ovaries (anovPCO) than in either ovPCO or controls, throughout the 24-hour study period. Despite the discrepancy in LH concentrations, basal serum concentrations of androstenedione were equally elevated in anovulatory and ovulatory women with PCO, compared with controls. There was a small but significant increase in androstenedione following GnRHa in both PCO groups at 24 hours but not in controls. A similar pattern was observed in the response of 17OHP to GnRHa although the response was significantly higher than controls in anovPCO women only. By contrast, the responses of both androstenedione and 17OHP to 250 micrograms synthetic ACTH were similar in PCO women to those in controls. These data provide evidence for ovarian hypersecretion of androgens in ovulatory, as well as anovulatory women with PCO, supporting the concept of abnormal regulation of 17-hydroxylase and (17,20-lyase activity in the ovary. The finding of an equal degree of hyperandrogenaemia in ovPCO and anovPCO groups, even though LH levels were much higher in the latter, suggests that hypersecretion of LH is not the primary cause of ovarian hyperandrogenism. Hyperandrogenism in PCOs may therefore represent an intrinsic abnormality of ovarian theca-interstitial cell function.
Article
Women with hyperandrogenic anovulation (HAA) have increased circulating levels of LH relative to those of FSH. The cause of this disturbance in gonadotropin secretion is uncertain. Previous investigations have sought to determine if increased GnRH drive is responsible for the excessive LH concentrations. Because previous results have conflicted, we addressed this question by comparing the 24-h secretory patterns of alpha-subunit and LH in women with HAA (n = 9) to those in eumenorrheic women in the midfollicular phase (n = 9). The mean (+/- SEM) pulse frequency was increased in women with HAA compared to that in eumenorrheic women of comparable age and percent ideal body weight for both LH (23.0 +/- 0.7 pulses/24 h vs. 3 17.1 +/- 1.7; P = 0.002) and alpha-subunit (23.0 +/- 0.8 vs. 19.1 +/- 1.2; P = 0.02). LH and alpha-subunit, but not FSH, responses to a submaximal dose of exogenous GnRH were increased in HAA, as were basal LH and alpha-subunit levels (P < 0.01). The present observations provide evidence for increased GnRH drive, including pulse frequency, in HAA. Although the results confirm the presence of a disturbance in gonadotropin secretion and suggest that its proximate cause may be of hypothalamic origin, they do not exclude the possibility that other factors, perhaps of ovarian origin, play a role in the establishment and/or maintenance of the altered gonadotropin secretory patterns and the chronic anovulation characteristic of HAA.
Article
The association between hyperinsulinaemia and hyperandrogenism in many women with polycystic ovarian syndrome (PCOS) implies roles for insulin and insulin-like growth factors (IGFs) in the regulation of ovarian androgen production. The aim of the present study was to compare the abilities of insulin, IGF-I and IGF-II to stimulate androgen production by human thecal cells in vitro. Serum-free monolayer cell cultures were established from the ovaries of euandrogenic women undergoing hysterectomy with oophorectomy for non-ovarian indications. Androgen (androstenedione) production was determined after 4 days of culture in the presence of insulin or either of the IGFs (10-100 ng/ml), with and without a maximal stimulatory dose of luteinizing hormone (LH; 10 ng/ml). Interactions with inhibin (30 ng/ml), a putative paracrine regulator of ovarian androgen synthesis, were also tested. The three metabolic hormones exerted similar dose-related effects on androgen production (ED50 < or = 10 ng/ml), which were augmented 2- to 3-fold in the presence of LH and further increased several-fold by the additional presence of inhibin. No treatment with insulin or either IGF stimulated thecal cell growth, but all treatments caused striking morphological changes consistent with enhanced steroidogenesis. These results reveal potent regulatory effects of metabolic hormones on human thecal androgen synthesis, which imply (i) 'progonadotrophic' roles for insulin and IGF-I in regulating normal ovarian androgen production, (ii) a role for insulin in the aetiology of hyperandrogenism (both with and without hyperinsulinism) in PCOS and (iii) paracrine roles for granulosa-derived IGF-II and inhibin in regulating ovarian androgen production.
Article
To evaluate the clinical relevance of testing pituitary-ovarian responses in patients suffering from polycystic ovary syndrome (PCOS) with the GnRH agonist nafarelin, a 1.2-mg dose of nafarelin was given intranasally to 19 women with PCOS and 15 healthy premenopausal women. The subsequent analysis of steroids in both serum and urine during the test was carried out at several time points for up to 24 h. Serum levels of 17 alpha-hydroxyprogesterone were elevated at all time points of the test in PCOS patients vs. controls [at baseline, 3.5 +/- 0.2 vs. 1.8 +/- 0.1 nmol/L (P < 0.001); at 24 h, 9.9 +/- 0.9 vs. 4.9 +/- 0.3 nmol/L (P < 0.001)]. Basal levels of androstenedione were higher in the patient group, but there was no significant change during the test in either group. Serum testosterone levels were also found to differ in PCOS patients compared with the control values at baseline (2.2 +/- 0.2 vs. 1.5 +/- 0.1 nmol/L; P < 0.05) and after nafarelin treatment (at 24 h, 3.2 +/- 0.4 vs. 1.8 +/- 0.2 nmol/L; P < 0.05). Serum estradiol levels rose significantly in both groups during the test; the posttest levels were significantly higher in PCOS than in controls. The PCOS patients displayed a significant increase in androgen and gestagen metabolites as well as in glucocorticoid metabolites excreted in the urine during the 24 h. In the control subjects, except for 17 alpha-hydroxypregnanolone, which rose significantly, none of the urinary steroids investigated showed relevant changes during the nafarelin test. The posttest excretion of allo-tetrahydrocortisol (1.4 +/- 0.2 vs. 0.3 +/- 0.1 mumol/g creatinine; P < 0.001) and the increase in 17 alpha-hydroxypregnanolone excretion (1.4 +/- 0.2 vs. 0.3 +/- 0.1 mumol/g creatinine; P < 0.001) were distinctly higher in PCOS patients than in the controls; the diagnostic sensitivity of the combination of both parameters was 89% at a 93% specificity. Thus, measurements of 17 alpha-hydroxyprogesterone levels in serum and of urinary allo-tetrahydrocortisol and 17 alpha-hydroxypregnanolone after nafarelin treatment make this stimulation test a valuable diagnostic tool for identifying PCOS patients. The significant changes in the excretion of urinary androgen and gestagen metabolites, unmasked by GnRH agonist stimulation, suggest a functional alteration of the pituitary-ovarian axis. The reason for the increased excretion of glucocorticoid metabolites after nafarelin stimulation remains to be clarified.
Article
Functional ovarian hyperandrogenism (FOH) is characterized by an abnormal ovarian response to challenge with the GnRH analogs nafarelin and leuprolide acetate, similar to that observed in women with well defined polycystic ovary syndrome, regardless of whether elevated LH levels or polycystic ovaries are present. We studied an unselected group of 42 hyperandrogenic adolescents (age range, 14-22 yr; mean, 18.1 +/- 2.5 yr) 1) to determine FOH incidence through the assessment of ovarian-steroidogenic response to a single dose of leuprolide acetate, 2) to assess the clinical characteristics of patients according to their responses to GnRH analog stimulation, and 3) to evaluate adrenal steroidogenic function and its relation to ovarian hyperandrogenism in patients with either normal or abnormal responses to leuprolide acetate challenge. All patients underwent leuprolide acetate and ACTH testing, dexamethasone and ovarian suppression tests, and pelvic ultrasonography. Twenty-four (58%) patients had supranormal plasma 17-hydroxyprogesterone (17-OHP) responses to leuprolide acetate characteristic of FOH, and in 18, the 17-OHP response was similar to that of controls (n = 24; age, 17.1 +/- 2.3 yr). Seven patients (5 with FOH and 2 with normal responses to leuprolide acetate) had an abnormal response to ACTH, but only 1 had conclusive evidence of 21-hydroxylase deficiency. In 16 patients, the response to both stimulation tests was normal. Only 13 (54%) of the 24 FOH patients had polycystic ovaries on ultrasonography, and in 11 (46%), basal plasma LH levels were elevated. In FOH patients, reduction in testosterone and androstenedione plasma levels was significantly greater after ovarian suppression than after dexamethasone challenge (P < 0.0005 and P < 0.02, respectively). Peak plasma 17-OHP levels postleoprolide acetate simulation correlated with dexamethasone-suppressed plasma testosterone concentrations, dexamethasone-suppressed plasma androstenedione levels, and the free androgen index postdexamethasone treatment (r = 0.4, P = 0.01; r+ 0.4, P < 0.05; and r = 0.41, P = 0.007, respectively), Plasma sex hormone-binding globulin levels after dexamethasone administration correlated negatively with the baseline free androgen index (r = -.0.67; P < 0.0001). Considering our diagnostic criteria, 26 (62%) of our collective of 42 patients had abnormal responses to one or both stimulation tests, whereas 16 (37%) had normal response. FOH is the most common cause in (58%) of androgen excess in adolescence. Short term leuprolide acetate stimulation is a reliable tool fro identification of the ovary as the source of their hyperandrogenism.
Article
Plasma 17-hydroxyprogesterone (17PROG) hyperresponsiveness to GnRH agonist (nafarelin) testing is typical of polycystic ovary syndrome and other functional ovarian hyperandrogenism (FOH) that does not meet customary criteria for the diagnosis of polycystic ovary syndrome. We have postulated that this results from abnormal regulation of androgen secretion. Whether this dysregulation is the result of a normal physiological response to ovarian hyperstimulation or escape from down-regulation of steroidogenesis is unknown. To distinguish between these possibilities, we have analyzed the ovarian steroid responses to nafarelin for the apparent efficiency of the steroidogenic steps and the apparent dose-response relationships between blood LH and steroid levels. We compared normal women (n = 18) with three groups of hyperandrogenic women (n = 15-19/group): patients with 17PROG hyperresponsiveness with or without elevated LH levels (type 1 and type 2 FOH, respectively) and patients with normal 17PROG responses to nafarelin (nafarelin negative). Subjects were pretreated with dexamethasone to suppress coincidental adrenal contributions to plasma steroid levels. The pattern of steroid secretion was similarly abnormal in both types of FOH, with the high LH group having generally more severe abnormalities in the levels of steroid intermediates. Baseline 17PROG and 17-hydroxypregnenolone and the ratio of 17PROG to androstenedione (AD) were increased (P < 0.05). In addition, the apparent slope of the 17PROG response to LH was significantly increased. Baseline levels of both AD and dehydroepiandrosterone and the AD response to nafarelin were increased, yet the ratio of peak minus baseline (delta) AD/delta 17PROG (another index of 17,20-lyase activity) was subnormal in FOH. The apparent slope of the testosterone (T) response to LH was significantly increased, and indexes of aromatase activity [estradiol (E2)/T and delta estradiol/delta T] were significantly decreased. Nafarelin stimulated plasma E2 in all groups to rise along an apparently similar LH-E2 dose-response slope. We interpret these results as indicating that FOH patients have generalized overactivity of thecal steroidogenesis, but nevertheless compensate so as to maintain a normal dose-response relationship between blood levels of LH and E2. FOH patients, whether they have LH excess or not, seen to form excessive 17PROG and incompletely dampen (down-regulate) thecal cell 17PROG, AD, and T secretion in response to LH stimulation. 17PROG hyperresponsiveness to nafarelin seems to be prominent both because it is formed in excess and because 17,20-lyase efficiency is rate limiting. The T elevation seems to arise mainly from overactive steroidogenesis, but also partly from an additional functional decrease in aromatase efficiency, which is secondary to negative feedback by the substrate-driven tendency toward estrogen excess.(ABSTRACT TRUNCATED AT 400 WORDS)
Article
Evidence suggests that hyperinsulinemic insulin resistance may reduce serum levels of the adrenal steroid dehydroepiandrosterone (DHEA) sulfate in humans. This study was conducted to assess the influence of physiological concentrations of insulin on serum adrenal steroid levels by lowering circulating insulin in nondiabetic men through the administration of the biguanide metformin. A total of 28 nondiabetic men were studied. The study group consisted of 16 obese and hypertensive men, and the control group of 12 nonobese and normotensive men. The men were studied at baseline and after the oral administration of 500 mg metformin, 3 times daily, for 21 days. Metformin administration resulted in significant reductions in serum insulin levels and concurrent increases in serum DHEA sulfate levels in both groups of men. The mean fasting serum DHEA sulfate concentration rose by 48% in the obese hypertensive men (from 5.9 +/- 0.8 to 8.7 +/- 0.7 mumol/L; P < 0.02) and by 80% in the nonobese normotensive men (from 3.5 +/- 0.5 to 6.3 +/- 0.9 mumol/L; P < 0.05). When the results from both groups were combined, changes in serum DHEA sulfate levels (i.e. day 21 value minus day 0 value) correlated positively with baseline fasting serum insulin levels (r = 0.44; P = 0.02; n = 28). Moreover, changes in fasting serum DHEA sulfate levels correlated inversely with changes in fasting serum insulin levels (r = -0.38; P < 0.05; n = 28). These findings lend further credence to the idea that insulin acts as a physiological regulator of DHEA sulfate metabolism and lowers circulating DHEA sulfate concentrations in men.
Article
To investigate if human thecal cells contain messenger ribonucleic acid (RNA) encoding insulin-like growth factor I (IGF-I) and insulin receptors and if IGF-I and insulin could stimulate androgen production in thecal cells. Poly-adenine+ RNA was extracted from fresh thecal tissue, and the expression of the genes encoding insulin and IGF-I receptors were analyzed. Isolated thecal cells were cultured 4 to 6 days with and without hormones. Procedures were performed in a university laboratory. Eight women in the follicular phase of natural cycles were undergoing gynecological laparotomy for reasons unrelated to ovarian pathology. The leading follicle(s) was excised, and dispersed cells of the theca interna layer were isolated through combined mechanical and enzymatic techniques. Luteinizing hormone (LH), IGF-I, and insulin were added to the cell cultures. The expression of IGF-I receptor and insulin receptor transcripts were analyzed by Northern blot. Medium levels of androstenedione and testosterone were measured by radioimmunoassay. In the separated thecal tissue both IGF-I receptor and insulin-receptor transcripts were detected. Insulin-like growth factor I and insulin potentiated LH-induced androgen secretion while having less pronounced effects on basal androgen production. The present study demonstrates that both insulin and IGF-I receptor genes are expressed and that insulin and IGF-I can stimulate steroid production in human thecal cells. The study provides further support for the hypothesis that IGF-I and insulin may be involved both in physiological regulation of ovarian function as well as in its pathophysiology.
Article
Recent data suggest that insulin is a modulator of ovarian and adrenal steroidogenesis and that, in the ovary of hyperandrogenic women, hyperinsulinemia might cause dysregulation of cytochrome P450c17 alpha activity. To further assess in vivo the effects of insulin on adrenal steroidogenesis, ACTH stimulation was carried out in 21 hyperandrogenic women during a 3-h hyperinsulinemic (80 mU/m2-min) euglycemic clamp. In all of these women the procedure was repeated during saline infusion as n control. In nonamenorrheic patients, the tests were performed in the early follicular phase of two different menstrual cycles. Serum cortisol, progesterone, 17-hydroxypregnenolone (17-OHJPREG). 17-hydroxyprogesterone (17-OHP), dehydroepiandrosterone (DHEA), and androstenedione (A) were measured after 2 h of insulin or saline infusion (zero time) and, subsequently, 30 and 60 min after an iv bolus of 0.25 mg ACTH-(1-24). At zero time, no difference was found in the serum steroid concentrations between the two protocols. ACTH-stimulated serum 17-OHPREG and, to a lesser extent, 17-OHP were significantly higher during insulin than during saline infusion (peaks, 60.6 +/- 9.0 vs. 40.7 +/- 7.9 and 7.7 +/- 7.7 vs. 6.6 +/- 0.6 nmol/L; P < 0.005 and P < 0.01, respectively). Serum DHEA was also slightly higher during hyperinsulinemia, although only after 30 min (54.5 +/- 3.0 vs. 48.2 +/- 4.2 nmol/L; P < 0.05). No statistically significant difference in the cortisol, progesterone, or androstenedione response to ACTH was found between the two protocols. ACTH-stimulated 17-OHPREG/DHEA and 17-OHP/A molar ratios, indexes of apparent 17,20-lyase activity, were significantly higher during the clamp studies than during saline infusion (by ANOVA, F = 12.8; P < 0.001 and F = 6.7; P < 0.005, respectively), suggesting an impaired enzyme activity. These in vivo data support the hypothesis that insulin potentiates ACTH-stimulated steroidogenesis. This effect of insulin seems to be associated with a relative impairment of 17,20-lyase activity.
Number 9 ؒ 623 androgenism does not improve peripheral or hepatic insulin resistance in the polycystic ovary syndrome
  • Reducing Serum Insulin And Ovarian
  • In Cytochrome
  • Ovary
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REDUCING SERUM INSULIN AND OVARIAN CYTOCHROME P450c17a IN POLYCYSTIC OVARY SYNDROME Volume 335 Number 9 ؒ 623 androgenism does not improve peripheral or hepatic insulin resistance in the polycystic ovary syndrome. J Clin Endocrinol Metab 1990;70:699-704.
Studies of the nature of 17-hydroxyprogesterone hyperresponsiveness to gonadotropin-releasing hormone agonist challenge in functional ovarian hyperandrogenism For personal use only. No other uses without permission
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Rosenfield RL, Barnes RB, Ehrmann DA. Studies of the nature of 17-hydroxyprogesterone hyperresponsiveness to gonadotropin-releasing hormone agonist challenge in functional ovarian hyperandrogenism. J Clin Endocrinol Metab 1994;79:1686-92. The New England Journal of Medicine Downloaded from nejm.org at TUFTS UNIVERSITY on December 9, 2014. For personal use only. No other uses without permission. Copyright © 1996 Massachusetts Medical Society. All rights reserved.
Role of obesity and insulin in the development of anovulation Ovulation induction: basic science and clinical advances
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Nestler JE. Role of obesity and insulin in the development of anovu-lation. In: Filicori M, Flamigni C, eds. Ovulation induction: basic science and clinical advances. Amsterdam: Elsevier Science B.V., 1994:103-14.
A direct effect of hyperinsulinemia on serum sex hormone-binding globulin levels in obese women with the polycystic ovary syndrome
  • Nestler JE
  • Powers LP
  • Matt DW