Effect of testosterone on insulin stimulated IRS1 Ser phosphorylation in primary rat myotubes--a potential model for PCOS-related insulin resistance

Androgen-induced upregulation of CFTR in pancreatic β-cell contributes to hyperinsulinemia in PCOS model

PURPOSE

Polycystic ovarian syndrome (PCOS) is an endocrine-metabolic condition affecting 5-10% of reproductive-aged women and characterized by hyperandrogenism, insulin resistance (IR), and hyperinsulinemia. CFTR is known to be regulated by steroid hormones, and our previous study has demonstrated an essential role of CFTR in β-cell function. This study aims to investigate the contribution of androgen and CFTR to hypersecretion of insulin in PCOS and the underlying mechanism.

METHODS

We established a rat PCOS model by subcutaneously implanting silicon tubing containing Dihydrotestosterone (DHT). Glucose tolerance test with insulin levels was performed at 9 weeks after implantation. A rat β-cell line RINm5F, a mouse β-cell line β-TC-6, and mouse islets were treated with DHT, and with or without the androgen antagonist flutamide for CFTR and insulin secretion-related functional assays or mRNA/protein expression measurement. The effect of CFTR inhibitors on DHT-promoted membrane depolarization, glucose-stimulated intracellular Ca2+ oscillation and insulin secretion were examined by membrane potential imaging, calcium imaging and ELISA, respectively.

RESULTS

The DHT-induced PCOS model showed increased body weight, impaired glucose tolerance, and higher blood glucose and insulin levels after glucose stimulation. CFTR was upregulated in islets of PCOS model and DHT-treated cells, which was reversed by flutamide. The androgen receptor (AR) could bind to the CFTR promoter region, which was enhanced by DHT. Furthermore, DHT-induced membrane depolarization, enhanced glucose-stimulated Ca2+ oscillations and insulin secretion, which could be abolished by CFTR inhibitors.

CONCLUSIONS

Excessive androgen enhances glucose-stimulating insulin secretion through upregulation of CFTR, which may contribute to hyperinsulinemia in PCOS.

The roles of sex hormones in the pathophysiology of age-related sarcopenia and frailty

Background

Sarcopenia is an age-related condition characterized by a progressive and systemic decline in skeletal muscle mass, quality, and strength. The incidence of sarcopenia contains sex-specific aspects, indicating the contribution of sex hormones to its pathophysiology. This review focuses on changing trends in sarcopenia, discusses alterations in definitions and diagnostic criteria, and emphasizes the association between sarcopenia and sex hormones.

Methods

A literature search was performed on PubMed for related articles published between 1997 and December 2023 using appropriate keywords.

Main Findings Results

Advances in research have emphasized the significance of muscle quality and strength over muscle mass, resulting in new diagnostic criteria for sarcopenia. Androgens demonstrated anabolic effects on skeletal muscles and played a significant role in the pathophysiology of sarcopenia. In clinical settings, androgen replacement therapy has exhibited certain positive outcomes for treating sarcopenia, despite concerns about potential side effects. Conversely, estrogen is involved in skeletal muscle maintenance, but the detailed mechanisms remain unclear. Moreover, results regarding the clinical application of estrogen replacement therapy for treating sarcopenia remained inconsistent.

Conclusion

The elucidation of molecular mechanisms that involve sex hormones is eagerly awaited for novel therapeutic interventions for sarcopenia.

A Rare Case of Hyperandrogenism Due to Fibrothecoma and Leydig Cell Tumor in a Postmenopausal Woman With Adrenal Adenoma: A Case Report and Literature Review

Hyperandrogenism is an endocrine disorder characterized by an elevated level of androgen in women, which can be due to several etiologies, including ovarian and adrenal causes. Hyperandrogenism can result in hirsutism and virilization in severe cases. Ovarian etiologies can include ovarian hyperthecosis, hilus cell tumors, arrhenoblastomas, and Leydig cell tumors. Diagnosing the specific cause requires comprehensive work, and management is then tailored to address the specific etiology. Treatment may include bilateral oophorectomy and gonadotropin-releasing hormone (GnRH) analogs in combination with antiandrogen therapy. Surgery, medical treatment, and radiation therapy are also options for patients with hypercortisolemia. We present the case of a 58-year-old female who presented with clinical features of hyperandrogenism, which were confirmed with biochemical testing. She was found to have a non-functioning adrenal adenoma with no significant abnormality on ovarian imaging and biochemical hyperandrogenemia due to fibrothecoma and Leydig cell tumor, which resolved after bilateral salpingo-oophorectomy.

Expression of genes in the AKT signalling pathway in human oocytes from patients with polycystic ovaries

Polycystic ovary syndrome is an endocrine disorder commonly found among females of reproductive age. Different factors have been correlated with this syndrome, although the aetiology of the disease is still unrecognized with both environmental and hereditary factors leading to the progression. Hormonal effects of the AKT pathway have made it an interesting study unit for PCOS cases. The aim of this study was to investigate the expression patterns of genes involved in the AKT pathway, including IRS1, IRS2, AKT1 and AKT2. In total, 13 human oocytes were collected for this study at the meiosis II stage, in which seven of them were collected from individuals with polycystic ovaries and the rest formed the control group of individuals with no signs of polycystic ovaries. RNA was extracted from oocytes and then the RNA was converted into cDNA for the real-time PCR process. Expression levels of four genes in the AKT pathway, in addition to housekeeping gene (ACTB), were evaluated. Expression levels of each gene were quantified using real-time PCR and statistical analysis was performed. The results of this study showed that there was no significant correlation between the expression of genes in oocyte samples obtained from patients with polycystic ovaries and the control group. This study is the first to evaluate the expression levels of genes involved in the AKT pathway in human oocyte samples. Therefore, it provides crucial information to form the basis of further studies.

Insulin resistance in polycystic ovary syndrome across various tissues: an updated review of pathogenesis, evaluation, and treatment

Polycystic ovary syndrome (PCOS) is a common endocrine disorder characterized by chronic ovulation dysfunction and overabundance of androgens; it affects 6-20% of women of reproductive age. PCOS involves various pathophysiological factors, and affected women usually have significant insulin resistance (IR), which is a major cause of PCOS. IR and compensatory hyperinsulinaemia have differing pathogeneses in various tissues, and IR varies among different PCOS phenotypes. Genetic and epigenetic changes, hyperandrogenaemia, and obesity aggravate IR. Insulin sensitization drugs are a new treatment modality for PCOS. We searched PubMed, Google Scholar, Elsevier, and UpToDate databases in this review, and focused on the pathogenesis of IR in women with PCOS and the pathophysiology of IR in various tissues. In addition, the review provides a comprehensive overview of the current progress in the efficacy of insulin sensitization therapy in the management of PCOS, providing the latest evidence for the clinical treatment of women with PCOS and IR.

Hyperandrogenism and Polycystic ovary syndrome: Effects in pregnancy and offspring development

Polycystic ovary syndrome (PCOS) is one of the major endocrine disorders affecting women of reproductive age. Its etiology remains unclear. It is suggested that environmental factors, and particularly the intrauterine environment, play key roles in PCOS development. Besides the role of androgens in PCOS pathogenesis, exposure to endocrine disruptors, as is Bisphenol A, could also contribute to its development. Although PCOS is considered one of the leading causes of ovarian infertility, many PCOS patients can get pregnant. Some of them by natural conception and others by assisted reproductive technique treatments. As hyperandrogenism (one of PCOS main features) affects ovarian and uterine functions, PCOS women, despite reaching pregnancy, could present high-risk pregnancies, including implantation failure, an increased risk of gestational diabetes, preeclampsia, and preterm birth. Moreover, hyperandrogenism may also be maintained in these women during pregnancy. Therefore, as an altered uterine milieu, including hormonal imbalance, could affect the developing organisms, monitoring these patients throughout pregnancy and their offspring development is highly relevant. The present review focuses on the impact of androgenism and PCOS on fertility issues and pregnancy-related outcomes and offspring development. The evidence suggests that the increased risk of pregnancy complications and adverse offspring outcomes of PCOS women would be due to the factors involved in the syndrome pathogenesis and the related co-morbidities. A better understanding of the involved mechanisms is still needed and could contribute to a better management of these women and their offspring. This article is categorized under: Reproductive System Diseases > Molecular and Cellular Physiology Reproductive System Diseases > Environmental Factors.

Controversies in the Pathogenesis, Diagnosis and Treatment of PCOS: Focus on Insulin Resistance, Inflammation, and Hyperandrogenism

Polycystic ovary syndrome (PCOS) is a heterogeneous and extremely common disease with symptoms that vary with the age of the patient, typically characterized by hyperandrogenism, chronic oligo-anovulation, and/or several metabolic disorders. The syndrome includes various phenotypes, and the pathogenesis is multifactorial, often involving insulin resistance. This feature is closely related to ovarian dysfunction, inflammation, hyperandrogenism, and metabolic disorders, which characterize and complicate the syndrome. Therapy currently considers both lifestyle improvements and medications, and must be tailored on a case-by-case basis. To date, the published studies have not arrived at a definition of the most suitable therapy for each individual case and many of the drugs used are still off-label. In this review, we discuss some controversial diagnostic and therapeutic aspects of PCOS, such as the role of insulin resistance, inflammation, and hyperandrogenism. We also evaluated the advantages and disadvantages of contraceptive therapy and antiandrogens.

Bilateral Leydig Cell Hyperplasia: A Rare Cause of Postmenopausal Hirsutism

Background

Postmenopausal hirsutism could be due to a myriad of causes, including ovarian and adrenal tumours, ovarian hyperthecosis, exogenous androgens, and Cushing's syndrome. We report a patient who was found to have a rare cause of postmenopausal hirsutism. Case Presentation. A 64-year-old postmenopausal woman with a history of hypertension, thyrotoxicosis, and poorly controlled diabetes on multiple oral hypoglycaemic agents presented with gradual onset progressive excessive hair growth without any virilizing features. On examination, she did not have Cushingnoid features or clitoromegaly. Her hirsutism was quantified with Ferriman–Gallwey score which was 9. Her biochemical evaluation showed elevated testosterone levels with normal DHEAS, ODST, 17-OHP, and prolactin. Low-dose dexamethasone suppression test did not suppress testosterone more than 40%. Contrast-enhanced CT of the adrenal and pelvis did not show any adrenal or ovarian mass lesions. Transvaginal ultrasound scan showed bilateral prominent ovaries only. Combined adrenal and ovarian venous sampling was carried out to localize the source of excess androgen, but only the left adrenal vein was successfully cannulated which showed suppressed testosterone level compared to periphery. The patient underwent total abdominal hysterectomy and bilateral salphingo oophorectomy, and her testosterone level normalized postoperatively. Her glycaemic control improved. Histology showed evidence of bilateral diffuse ovarian Leydig cell hyperplasia.

Conclusion

Evaluation of postmenopausal hirsutism needs careful history and examination followed by biochemical evaluation and imaging. While adrenal and ovarian venous sampling can help to arrive at a diagnosis, it is a technically demanding procedure with low success rates even at centers of excellence. Therefore, in such situations, bilateral oophorectomy may be the best course of action which will give the histological confirmation of the diagnosis. Successful treatment of hyperandrogenism can result in improvement of glycaemic control. Bilateral diffuse Leydig cell hyperplasia is a rare but important cause of postmenopausal hirsutism.

A comparison between the effect of trans-anethole and metformin on biochemical parameters of polycystic ovary syndrome in rats

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.

Pathophysiology of Physical Inactivity-Dependent Insulin Resistance: A Theoretical Mechanistic Review Emphasizing Clinical Evidence

The modern lifestyle has a negative impact on health. It is usually accompanied by increased stress levels and lower physical activity, which interferes with body homeostasis. Diabetes mellitus is a relatively common metabolic disorder with increasing prevalence globally, associated with various risk factors, including lower physical activity and a sedentary lifestyle. It has been shown that sedentary behavior increases the risk of insulin resistance, but the intermediate molecular mechanisms are not fully understood. In this mechanistic review, we explore the possible interactions between physical inactivity and insulin resistance to help better understand the pathophysiology of physical inactivity-dependent insulin resistance and finding novel interventions against these deleterious pathways.

Increased Skeletal Muscle Fiber Cross-Sectional Area, Muscle Phenotype Shift, and Altered Insulin Signaling in Rat Hindlimb Muscles in a Prenatally Androgenized Rat Model for Polycystic Ovary Syndrome

Women with polycystic ovary syndrome (PCOS) are reported to have greater lean mass and insulin resistance. To examine muscular changes in a prenatally androgenized (PNA) rat model for PCOS, Sprague-Dawley rats were exposed to 5 mg testosterone or vehicle daily on gestational days 16-19. At 15 weeks of age, endurance on a rota-rod treadmill was measured. At 16 weeks of age, fasting blood glucose and insulin, hindlimb skeletal muscle mass, muscle fiber cross-sectional area (CSA) and composition, and intra- and peri-muscular lipid droplets were examined. Expression of mitochondrial marker ATP synthase and insulin signaling proteins were also investigated. Compared with controls, PNA female rats demonstrated greater total body and hindlimb muscle weights, greater muscle fiber CSA, and trending reduced time on the rota-rod. An increase in fibers co-expressing the slow and fast isoforms of myosin (90 vs. 86%, p < 0.05) and greater expression of ATP synthase (6-fold, p < 0.005) were observed in the gastrocnemius (GN) muscle. More lipid content was observed in GN and tibialis anterior (TA) muscles. PNA rats had elevated fasting serum insulin (1.9 vs. 1.2 ng/mL, p < 0.005) but comparable fasting glucose. Expression of total and Ser^636/9-phosphorylated IRS1 were altered in PNA rat hindlimb muscles. Together, skeletal muscle alterations in hindlimb muscles of a PNA rat model for PCOS may represent consequences of, or adaptations to, insulin resistance in this model.

Preoperative Oral Carbohydrate Reduces Postoperative Insulin Resistance by Activating AMP-Activated Protein Kinase after Colorectal Surgery

BACKGROUND

Postoperative insulin resistance (PIR) is a common response after colorectal surgery and an independent risk factor for recovery. Preoperative oral carbohydrate (POC) has been known to reduce PIR. Herein, we investigated whether its mechanism of action involves AMP-activated protein kinase (AMPK) and mTOR/S6K1/insulin receptor substrate-1 (IRS-1) pathways.

METHODS

Patients undergoing colorectal cancer resection were randomly assigned to a POC, fasting, or placebo group. The exclusion criteria were association with diseases or intake of medication affecting insulin sensitivity. Pre- and postoperative insulin resistance, and protein phosphorylation of AMPK, mTOR, and IRS-1 in the rectus abdominis muscle were evaluated.

RESULTS

From January 2017 to December 2017, 70 patients were randomized and 63 were evaluated. No difference was found in the clinical and operative characteristics among the 3 groups. In the POC group, the levels of blood glucose, blood insulin, and homeostasis model assessment of insulin resistance were significantly lower in the POC group than the fasting and placebo groups, and the insulin sensitivity index was significantly higher. The phosphorylation of AMPK in the POC group was significantly higher than that in the other 2 groups, whereas the phosphorylation of mTOR and IRS-1 was significantly lower.

CONCLUSION

PIR involves AMPK and mTOR/S6K1/IRS-1 pathways. POC reduces PIR by the stimulation of AMPK, which suppresses the phosphorylation of mTOR/IRS-1 and attenuates PIR after colorectal resection.

Comparative study of testosterone and vitamin D analogue, elocalcitol, on insulin-controlled signal transduction pathway regulation in human skeletal muscle cells

PURPOSE

Skeletal muscle (Skm) plays a key role in regulating energetic metabolism through glucose homeostasis. Several hormones such as Testosterone (T) and Vitamin D (VD) have been shown to affect energy-dependent cell trafficking by determining Insulin (I)-like effects.

AIM

To elucidate possible hormone-related differences on muscular metabolic control, we analyzed and compared the effects of T and elocalcitol (elo), a VD analogue, on the activation of energy-dependent cell trafficking, metabolism-related-signal transduction pathways and transcription of gene downstream targets.

METHODS

Human fetal skeletal muscle cells (Hfsmc) treated with T or elo were analyzed for GLUT4 localization, phosphorylation/activation status of AKT, ERK1/2, IRS-1 signaling and c-MYC protein expression.

RESULTS

T, similar to elo, induced GLUT4 protein translocation likely in lipid raft microdomains. While both T and elo induced a rapid IRS-1 phosphorylation, the following dynamic in phosphorylation/activation of AKT and ERK1/2 signaling was different. Moreover, T but not elo increased c-MYC protein expression.

CONCLUSIONS

All together, our evidence indicates that whether both T and elo are able to affect upstream I-like pathway, they differently determine downstream effects in I-dependent cascade, suggesting diverse physiological roles in mediating I-like response in human skeletal muscle.

Metabolic disturbances in non-obese women with polycystic ovary syndrome: a systematic review and meta-analysis

OBJECTIVE

To explore metabolic disturbances in nonobese women with polycystic ovary syndrome (PCOS) compared with nonobese healthy controls.

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Nonobese women with PCOS and nonobese healthy controls.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Prevalence of metabolic disturbances including hyperinsulinemia, insulin resistance (IR), impaired fasting glucose (IFG), impaired glucose intolerance (IGT), prediabetes, dyslipidemia, hypercholesterolemia, hypertriglyceridemia, and low high-density lipoprotein (low-HDL), as well as other metabolic outcomes such as type 2 diabetes mellitus (T2DM), hypertension, metabolic syndrome (Mets), myocardial infarction, stroke, cerebrovascular accident, arterial occlusive disease, and coronary heart disease.

RESULT(S)

Compared to nonobese controls, nonobese women with PCOS showed a higher prevalence of hyperinsulinemia (odds ratio [OR], 36.27; 95% confidence interval [CI] 1.76-747.12), IR (OR, 5.70; 95% CI 1.46-22.32), IGT (OR, 3.42; 95% CI 1.56-7.52), T2DM (OR, 1.47; 95% CI 1.11-1.93), hypertriglyceridemia (OR, 10.46; 95% CI 1.39-78.56), low-HDL (OR, 4.03; 95% CI 1.26-12.95), and Mets (OR, 2.57; 95% CI 1.30-5.07). No significant difference was observed for IFG, pre-DM, dyslipidemia, hypercholesterolemia, and hypertension. In subgroup analysis, Whites exhibited increased risks of IR, IGT, IFG, T2DM, hypertension, and Mets, whereas no significant metabolic change was found in Asians. No study reported specifically an incidence of myocardial infarction, stroke, cerebrovascular accident, arterial occlusive disease, and coronary heart disease in nonobese women with PCOS.

CONCLUSION(S)

Nonobese women with PCOS also suffer from metabolic disturbances and the risk of long-term metabolic complications. Further efforts should be made to elucidate underlying mechanisms and possible interventions in the early phase.

Metformin improves ovarian follicle dynamics by reducing theca cell proliferation and CYP-17 expression in an androgenized rat model

Background

Metformin influences insulin receptor signaling, which might interfere with the proliferation of ovarian follicular structures and steroidogenesis. We hypothesize that reductions in glucose and insulin levels might interfere with CYP-17 expression and histomorphological changes in an androgenized rat model. The aim of this study was to analyze the effect of metformin on CYP-17 expression, follicular dynamics, and proliferative parameters in neonatally androgenized female rats.

Methods

Thirty-six newborn rats were randomly allocated to the following three groups on the third day of life: control (CG, n = 12), androgenized (GA, n = 12), and androgenized + metformin (GAmet, n = 12). The GA and GAmet animals were administered 0.1 mL of testosterone propionate (1.25 mg/animal) diluted in castor oil (vehicle) in a single dose; the CG rats received a subcutaneous injection of the vehicle in the dorsum. After 90 days, gavage treatment was initiated, distilled water was administered to the CG and GA rats, and metformin (150 mg/kg) was administered to the GAmet animals. The treatment was administered daily for six weeks. Following anesthesia, blood was drawn for biochemical measurements, and the ovaries were removed for histological and immunohistochemical analyses of Ki67, VEGFA and CYP17 expression. The glucose and insulin levels were also measured.

Results

The comparison of the GA and GAmet animals revealed that metformin decreased the weight as well as the glucose and insulin levels, slowed the proliferation of the theca interna and interstitial cells, as evidenced by Ki-67 and VEGF-A expression, and diminished CYP17 expression in the analyzed ovarian structures. In addition, metformin reduced the number of degenerating follicles and interstitial cells and improved angiogenesis.

Conclusion

Metformin improves the carbohydrate metabolism, reduces proliferation, and decreases CYP-17 expression in the follicular structures of androgenized rats.

Dehydroepiandrosterone-induced activation of mTORC1 and inhibition of autophagy contribute to skeletal muscle insulin resistance in a mouse model of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in women of reproductive age and also an important metabolic disorder associated with insulin resistance (IR). Hyperandrogenism is a key feature of PCOS. However, whether hyperandrogenism can cause IR in PCOS remains largely unknown. The mammalian target of rapamycin complex 1 (mTORC1) and its regulated autophagy are closely associated with IR. In the present study, we investigated the role of mTORC1-autophagy pathway in skeletal muscle IR in a dehydroepiandrosterone (DHEA)-induced PCOS mouse model. DHEA-treated mice exhibited whole-body and skeletal muscle IR, along with the activated mTORC1, repressed autophagy, impaired mitochondria, and reduced plasma membrane glucose transporter 4 (GLUT4) expression in skeletal muscle of the mice. In cultured C2C12 myotubes, treatment with high dose testosterone activated mTORC1, reduced autophagy, impaired mitochondria, decreased insulin-stimulated glucose uptake, and induced IR. Inhibition of mTORC1 or induction of autophagy restored mitochondrial function, up-regulated insulin-stimulated glucose uptake, and increased insulin sensitivity. On the contrary, inhibition of autophagy exacerbated testosterone-induced impairment. Our findings suggest that the mTORC1-autophagy pathway might contribute to androgen excess-induced skeletal muscle IR in prepubertal female mice by impairing mitochondrial function and reducing insulin-stimulated glucose uptake. These data would help understanding the role of hyperandrogenism and the underlying mechanism in the pathogenesis of skeletal muscle IR in PCOS.

Androgen interacts with exercise through the mTOR pathway to induce skeletal muscle hypertrophy

This study was designed to investigate the effects of exogenous androgen and resistance exercise on skeletal muscle hypertrophy and the role of the mammalian target of rapamycin (mTOR) signalling during the process. A total of 24 male Sprague-Dawley rats were randomly assigned to sham operation and dihydrotestosterone (DHT) implantation groups with subgroups subjected to sedentary conditions or resistance exercise (SHAM+SED, SHAM+EX, DHT+SED, and DHT+EX). The experimental procedure lasted for 10 days. The mRNA expression of androgen receptor (AR) and insulin-like growth factor I (IGF-I), the expression of myosin heavy chain (MHC), as well as the phosphorylation statuses of AR, mTOR, p70 ribosomal S6 kinase (p70S6K), and eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1) were determined in the white gastrocnemius muscle. The cross sectional area and wet mass of the muscle were also measured. The cross sectional area and MHC expression were significantly higher in SHAM+EX, DHT+SED, and DHT+EX than in SHAM+SED. There was no significant difference among groups in muscle mass. The mRNA expression of AR and IGF-I and the phosphorylation of mTOR, p70S6K, and 4EBP1 were significantly increased in DHT+SED and SHAM+EX and were significantly enhanced in DHT+EX compared with either DHT or exercise alone. These data show that DHT causes hypertrophy in skeletal muscle and that exercise has a synergistic effect on DHT-induced hypertrophy. Exercise enhances androgen-induced rapid anabolic action, which involves activation of the mTOR pathway.

New Insights into mTOR Signal Pathways in Ovarian-Related Diseases: Polycystic Ovary Syndrome and Ovarian Cancer

mTOR, the mammalian target of rapamycin, is a conserved serine/threonine kinase which belongs to the phosphatidyl-linositol kinase-related kinase (PIKK) family. It has two complexes called mTORC1 and mTORC2. It is well established that mTOR plays important roles in cell growth, proliferation and differentiation. Over-activation of the mTOR pathway is considered to have a relationship with the development of many types of diseases, including polycystic ovary syndrome (PCOS) and ovarian cancer (OC). mTOR pathway inhibitors, such as rapamycin and its derivatives, can directly or indirectly treat or relieve the symptoms of patients suffering from PCOS or OC. Moreover, mTOR inhibitors in combination with other chemical-molecular agents may have extraordinary efficacy. This paper will discuss links between mTOR signaling and PCOS and OC, and explore the mechanisms of mTOR inhibitors in treating these two diseases, with conclusions regarding the most effective therapeutic approaches.

Metabolic actions of insulin in ovarian granulosa cells were unaffected by hyperandrogenism

Polycystic ovary syndrome (PCOS) patients have intra-ovarian hyperandrogenism and granulosa cells (GCs) from PCOS patients have impaired insulin-dependent glucose metabolism and insulin resistance. The purpose of this study is to determine whether excess androgen affects glucose metabolism and induces insulin resistance of GCs. We firstly explored the insulin metabolic signaling pathway and glucose metabolism in cultured GCs. The Akt phosphorylation and lactate production were increased after insulin treatment. Pre-treatment with PI3-K inhibitor attenuated insulin-induced phosphorylation of Akt and lactate accumulation. However, after treating GCs with different concentrations of testosterone for 5 days, insulin-induced phosphorylation of Akt and lactate production showed no significant change comparing with those of control cells. Finally, mRNA expression of insulin signaling mediators including INSR, IRS-1, IRS-2, and GLUT-4 in GCs was also not significantly altered after testosterone treatment. In conclusion, insulin activates PI3-K/Akt signaling pathway and promotes lactate production in ovarian GCs, but high androgen exerted no obvious influence on insulin signaling pathway and metabolic effect in GCs, suggesting that metabolic actions of insulin in ovarian GCs were unaffected by hyperandrogenism directly.

Western-style diet, sex steroids and metabolism

The evolutionary transition from hunting to farming was associated with introduction of carbohydrate-rich diets. Today, the increased consumption of simple sugars and high-fat food brought about by Western-style diet and physical inactivity are leading causes of the growing obesity epidemic in the Western society. The extension of human lifespan far beyond reproductive age increased the burden of metabolic disorders associated with overnutrition and age-related hypogonadism. Sex steroids are essential regulators of both reproductive function and energy metabolism, whereas their imbalance causes infertility, obesity, glucose intolerance, dyslipidemia, and increased appetite. Clinical and translational studies suggest that dietary restriction and weight control can improve metabolic and reproductive outcomes of sex hormone-related pathologies, including testosterone deficiency in men and natural menopause and hyperandrogenemia in women. Minimizing metabolic and reproductive decline through rationally designed diet and exercise can help extend human reproductive age and promote healthy aging. This article is part of a Special Issue entitled: Oxidative Stress and Mitochondrial Quality in Diabetes/Obesity and Critical Illness Spectrum of Diseases - edited by P. Hemachandra Reddy.

A nontargeted study of muscle proteome in severely obese women with androgen excess compared with severely obese men and nonhyperandrogenic women

OBJECTIVE

Androgen excess in women is frequently associated with muscle insulin resistance, especially in obese women with polycystic ovary syndrome. However, whether this is a primary event or the result of indirect mechanisms is currently debated.

DESIGN

This is an observational study.

METHODS

We obtained skeletal muscle biopsies during bariatric surgery from severely obese men (n=6) and women with (n=5) or without (n=5) androgen excess. We used two-dimensional differential gel electrophoresis and matrix-assisted laser desorption/ionization-time-of-flight/time-of-flight mass spectrometry to identify muscle proteins showing differences in abundance between the groups of obese subjects.

RESULTS

Women with hyperandrogenism presented the lowest abundances of glycogen phosphorylase, pyruvate kinase, β-enolase, glycerol-3-phosphate dehydrogenase, creatine kinase M-type, and desmin, whereas the abundances of these molecules were similar in control women and men.

CONCLUSION

According to our nontargeted proteomic approach, women with hyperandrogenism show a specific alteration of the skeletal muscle proteome that could contribute to their insulin resistance. Because men do not show similar results, this alteration does not appear to be the direct effect on muscle of androgen excess, but rather the consequence of indirect mechanisms that merit further studies.

Hyperandrogenism Decreases GRP78 Protein Level and Glucose Uptake in Human Endometrial Stromal Cells

BACKGROUND

Women with polycystic ovary syndrome (PCOS) exhibit a low fertility by chronic hyperandrogenemia. Different evidence have shown that androgens could regulate the endoplasmic reticulum (ER) homeostasis and glucose metabolism. However, it is unclear whether androgens can exert these effects on human endometrial stromal cells. Our goal was to study the protein content of GRP78 (an ER homeostasis marker) in endometria from women with PCOS and healthy women and to assess the GRP78 protein levels and its relationship with glucose uptake on a human endometrial stromal cell line stimulated with testosterone.

METHODS

Immunohistochemistry assays for GRP78 were performed on endometrial samples obtained from women with PCOS (n = 8) and control women subjected to hysterectomy (n = 8). Western blot analysis for GRP78 and glucose uptake was assessed in a telomerase-immortalized human endometrial stromal cell line (T-HESC) exposed to testosterone for 24 or 48 hours and challenged to an insulin short-term stimulation. Tukey test was performed for human samples comparison. Student t test or ANOVA-Bonferroni test was carried out according to the in vitro experiment. P < .05 was considered as significant.

RESULTS

GRP78 stromal immunostaining was reduced in PCOS endometria compared to controls (P < .05). The T-HESC shows a testosterone-dependent downregulation of GRP78 protein content (P < .05), concomitant with half-reduction in glucose uptake compared to controls (P < .05). Moreover, enhanced small interfering RNA against GRP78 messenger RNA leads to a decrease in glucose uptake (P < .05). Such effects were reverted by hydroxyflutamide, an inhibitor of androgen receptor.

CONCLUSION

These results suggest that hyperandrogenemic PCOS environment could compromise the endometrial homeostasis confirmed by the decrease in glucose uptake induced by testosterone and exhibited by stromal cells.

Scientific Statement on the Diagnostic Criteria, Epidemiology, Pathophysiology, and Molecular Genetics of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a heterogeneous and complex disorder that has both adverse reproductive and metabolic implications for affected women. However, there is generally poor understanding of its etiology. Varying expert-based diagnostic criteria utilize some combination of oligo-ovulation, hyperandrogenism, and the presence of polycystic ovaries. Criteria that require hyperandrogenism tend to identify a more severe reproductive and metabolic phenotype. The phenotype can vary by race and ethnicity, is difficult to define in the perimenarchal and perimenopausal period, and is exacerbated by obesity. The pathophysiology involves abnormal gonadotropin secretion from a reduced hypothalamic feedback response to circulating sex steroids, altered ovarian morphology and functional changes, and disordered insulin action in a variety of target tissues. PCOS clusters in families and both female and male relatives can show stigmata of the syndrome, including metabolic abnormalities. Genome-wide association studies have identified a number of candidate regions, although their role in contributing to PCOS is still largely unknown.

TallyHO obese female mice experience poor reproductive outcomes and abnormal blastocyst metabolism that is reversed by metformin

Obese women experience worse reproductive outcomes than normal weight women, specifically infertility, pregnancy loss, fetal malformations and developmental delay of offspring. The aim of the present study was to use a genetic mouse model of obesity to recapitulate the human reproductive phenotype and further examine potential mechanisms and therapies. New inbred, polygenic Type 2 diabetic TallyHO mice and age-matched control C57BL/6 mice were superovulated to obtain morula or blastocyst stage embryos that were cultured in human tubal fluid (HTF) medium. Deoxyglucose uptake was determined for individual insulin-stimulated blastocysts. Apoptosis was detected by confocal microscopy using the terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL) assay and Topro-3 nuclear dye. Embryos were scored for TUNEL-positive as a percentage of total nuclei. AMP-activated protein kinase (AMPK) activation, tumour necrosis factor (TNF)-α expression and adiponectin expression were analysed by western immunoblot and confocal immunofluorescent microscopy. Lipid accumulation was assayed by BODIPY. Comparisons were made between TallyHO morulae cultured to blastocyst embryos in either HTF medium or HTF medium with 25 μg mL(-1) metformin. TallyHO mice developed whole body abnormal insulin tolerance, had decreased litter sizes and increased non-esterified fatty acid levels. Blastocysts from TallyHO mice exhibited increased apoptosis, decreased insulin sensitivity and decreased AMPK. A possible cause for the insulin resistance and abnormal AMPK phosphorylation was the increased TNF-α expression and lipid accumulation, as detected by BODIPY, in TallyHO blastocysts and decreased adiponectin. Culturing TallyHO morulae with the AMPK activator metformin led to a reversal of all the abnormal findings, including increased AMPK phosphorylation, improved insulin-stimulated glucose uptake and normalisation of lipid accumulation. Women with obesity and insulin resistance experience poor pregnancy outcomes. Previously we have shown in mouse models of insulin resistance that AMPK activity is decreased and that activators of AMPK reverse poor embryo outcomes. Here, we show for the first time using a genetically altered obese model, not a diet-induced model, that metformin reverses many of the adverse effects of obesity at the level of the blastocyst. Expanding on this we determine that activation of AMPK via metformin reduces lipid droplet accumulation, presumably by eliminating the inhibitory effects of TNF-α, resulting in normalisation of fatty acid oxidation and HADH2 (hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase (trifunctional protein), alpha subunit) activity. Metformin exposure in vitro was able to partially reverse these effects, at the level of the blastocyst, and may thus be effective in preventing the adverse effects of obesity on pregnancy and reproductive outcomes.

Potent therapeutic effects of shouwu jiangqi decoction on polycystic ovary syndrome with insulin resistance in rats

OBJECTIVE

To investigate the effect of Shouwu Jiangqi Decoction (SJD) on polycystic ovary syndrome (PCOS) with insulin resistance (IR) in rats and to explore the underlining molecular mechanisms.

METHODS

A total of 51 female Sprague-Dawley rats were randomly divided into 6 groups: control group (n=7), model group (n=8), SJD high-dose group (n=9), SJD medium-dose group (n=9), SJD low-dose group (n=9) and DMBG group (n=9). Radioimmunoassay was used to measure serum follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone concentrations and qRT-PCR and western blot were used to examine the expression levels of mRNA and protein respectively of insulin receptor substrate 1 (IRS-1) and phosphatidylinositide 3-kinases (PI3K) p85α in different groups.

RESULTS

FSH level significantly decreased in the model group compared with the normal control (P<0.01), and high-dose SJD and DMBG can significantly increase FSH level (P<0.01). LH level showed a mild increase without statistic significance in the model group compared with the control and different dosages of SJD had no significance effect on LH level, while DMBG can significantly decrease LH level (P<0.01). Testosterone level significantly increased in the model group compared with the control group (P<0.01), and high-dose SJD and DMBG can significantly decrease testosterone level (P<0.01). The expression of IRS-1 as well as PI3Kp85α were significantly decreased in the model group compared with the normal control group at both mRNA (P<0.001) and protein (P<0.01) level, and both high-dose SJD and DMBG can enhance IRS-1 and PI3K expression (P<0.05).

CONCLUSIONS

SJD has potent therapeutic effects on PCOS with IR in rats. The therapeutic effects of SJD on IR and ovulatory dysfunction are probably achieved through correcting the defective insulin signaling transduction.

Testosterone and obesity

Testosterone is a key hormone in the pathology of metabolic diseases such as obesity. Low testosterone levels are associated with increased fat mass (particularly central adiposity) and reduced lean mass in males. These morphological features are linked to metabolic dysfunction, and testosterone deficiency is associated with energy imbalance, impaired glucose control, reduced insulin sensitivity and dyslipidaemia. A bidirectional relationship between testosterone and obesity underpins this association indicated by the hypogonadal-obesity cycle and evidence weight loss can lead to increased testosterone levels. Androgenic effects on enzymatic pathways of fatty acid metabolism, glucose control and energy utilization are apparent and often tissue specific with differential effects noted in different regional fat depots, muscle and liver to potentially explain the mechanisms of testosterone action. Testosterone replacement therapy demonstrates beneficial effects on measures of obesity that are partially explained by both direct metabolic actions on adipose and muscle and also potentially by increasing motivation, vigour and energy allowing obese individuals to engage in more active lifestyles. The degree of these beneficial effects may be dependent on the treatment modality with longer term administration often achieving greater improvements. Testosterone replacement may therefore potentially be an effective adjunctive treatment for weight management in obese men with concomitant hypogonadism.

Androgen Receptor Coregulator CTBP1-AS Is Associated With Polycystic Ovary Syndrome in Chinese Women: A Preliminary Study

Polycystic ovary syndrome (PCOS) is currently considered a predominantly hyperandrogenic syndrome. In theory, hyperandrogenism can be caused by high level of testosterone (T) as well as by enhanced androgen receptor (AR) activity. C-Terminal binding protein 1 antisense (CTBP1-AS) was a novel long noncoding RNA (lncRNA) to regulate AR activity. In this study, we found that expression level of CTBP1-AS in peripheral blood leukocytes was significantly higher in women with PCOS than that in controls after adjustment for age and body mass index (BMI). Individuals having higher expression of CTBP1-AS had significantly greater disease risk than those having lower expression. We also identified expression of CTBP1-AS as an independent risk factor for PCOS. A positive correlation was observed between the CTBP1-AS expression and the total T (TT) concentration either unadjusted or after adjusting for age, BMI, and homeostatic model assessment insulin resistance. Taken together, our current study presented the first evidence that the lncRNA CTBP1-AS, a novel AR modulator, is associated with PCOS in Chinese population and established the possibility that abnormal CTBP1-AS expression is a risk factor for PCOS and it is a predictor of variability in serum TT level in Chinese women with PCOS.

Excess of nerve growth factor in the ovary causes a polycystic ovary-like syndrome in mice, which closely resembles both reproductive and metabolic aspects of the human syndrome

Polycystic ovarian syndrome (PCOS), the most common female endocrine disorder of unknown etiology, is characterized by reproductive abnormalities and associated metabolic conditions comprising insulin resistance, type 2 diabetes mellitus, and dyslipidemia. We previously reported that transgenic overexpression of nerve growth factor (NGF), a marker of sympathetic hyperactivity, directed to the ovary by the mouse 17α-hydroxylase/C17-20 lyase promoter (17NF mice), results in ovarian abnormalities similar to those seen in PCOS women. To investigate whether ovarian overproduction of NGF also induces common metabolic alterations of PCOS, we assessed glucose homeostasis by glucose tolerance test, plasma insulin levels, and body composition by dual-energy x-ray absorptiometry scan in young female 17NF mice and wild-type mice. 17NF mice exhibited increased body weight and alterations in body fat distribution with a greater accumulation of visceral fat compared with sc fat (P < .01). 17NF mice also displayed glucose intolerance (P < .01), decreased insulin-mediated glucose disposal (P < .01), and hyperinsulinemia (P < .05), which, similar to PCOS patients, occurred independently of body weight. Additionally, 17NF mice exhibited increased sympathetic outflow observed as increased interscapular brown adipose tissue temperature. This change was evident during the dark period (7 pm to 7 am) and occurred concomitant with increased interscapular brown adipose tissue uncoupling protein 1 expression. These findings suggest that overexpression of NGF in the ovary may suffice to cause both reproductive and metabolic alterations characteristic of PCOS and support the hypothesis that sympathetic hyperactivity may contribute to the development and/or progression of PCOS.

Dihydrotestosterone deteriorates cardiac insulin signaling and glucose transport in the rat model of polycystic ovary syndrome

It is supposed that women with polycystic ovary syndrome (PCOS) are prone to develop cardiovascular disease as a consequence of multiple risk factors that are mostly related to the state of insulin resistance and consequent hyperinsulinemia. In the present study, we evaluated insulin signaling and glucose transporters (GLUT) in cardiac cells of dihydrotestosterone (DHT) treated female rats as an animal model of PCOS. Expression of proteins involved in cardiac insulin signaling pathways and glucose transporters, as well as their phosphorylation or intracellular localization were studied by Western blot analysis in DHT-treated and control rats. Treatment with DHT resulted in increased body mass, absolute mass of the heart, elevated plasma insulin concentration, dyslipidemia and insulin resistance. At the molecular level, DHT treatment did not change protein expression of cardiac insulin receptor and insulin receptor substrate 1, while phosphorylation of the substrate at serine 307 was increased. Unexpectedly, although expression of downstream Akt kinase and its phosphorylation at threonine 308 were not altered, phosphorylation of Akt at serine 473 was increased in the heart of DHT-treated rats. In contrast, expression and phosphorylation of extracellular signal regulated kinases 1/2 were decreased. Plasma membrane contents of GLUT1 and GLUT4 were decreased, as well as the expression of GLUT4 in cardiac cells at the end of androgen treatment. The obtained results provide evidence for alterations in expression and especially in functional characteristics of insulin signaling molecules and glucose transporters in the heart of DHT-treated rats with PCOS, indicating impaired cardiac insulin action.

Serum sex steroids and steroidogenesis-related enzyme expression in skeletal muscle during experimental weight gain in men

OBJECTIVES

Low-circulating testosterone is associated with development of type 2 diabetes in obese men. In this study, we examined the effects of experimental overfeeding and weight gain on serum levels of sex hormones and skeletal muscle expression of steroidogenic enzymes in healthy men with (FH+) and without (FH-) a family history of type 2 diabetes.

METHODS

Following a 3-day lead in energy balanced diet, FH+ (n = 9) and FH- men (n = 11) were overfed by 5200 kJ/day (45% fat) for 28 days. Body weight, fasting glucose, insulin, sex steroid, sex hormone binding globulin (SHBG) levels, insulin sensitivity (hyperinsulinaemic-euglycaemic clamp) and body fat (DXA) were assessed in all individuals at baseline and day 28, and sex steroidogenesis-related enzyme expression in vastus lateralis biopsies was examined in a subset (n = 11).

RESULTS

Body weight, fat mass and fasting insulin levels were increased by overfeeding (P < 0.01) and insulin was increased significantly more in FH+ men (P<0.01). Serum sex hormone binding globulin (SHBG) and 5α-dihydrotestosterone (DHT) were reduced with overfeeding (P < 0.05), and serum testosterone and DHT were reduced to a greater extent in FH+ men (P < 0.05). Overfeeding reduced mRNA expression of 3β-hydroxysteroid dehydrogenase (HSD) and 17βHSD (P ≤ 0.007), independently of group. 5α-Reductase (SRD5A1) mRNA expression was not changed overall, but a time by group interaction was observed (P = 0.04).

CONCLUSION

Overfeeding reduced SHBG and muscle expression of enzymes involved in the formation of testosterone in skeletal muscle. Men with a family history of T2DM were more susceptible to deleterious outcomes of overfeeding with greater reductions in serum testosterone and DHT and greater increases in markers of insulin resistance, which may contribute to increased risk of developing type 2 diabetes.

Polycystic ovary syndrome, insulin resistance, and obesity: navigating the pathophysiologic labyrinth

Polycystic ovary syndrome (PCOS) is a highly prevalent endocrine-metabolic disorder that implies various severe consequences to female health, including alarming rates of infertility. Although its exact etiology remains elusive, it is known to feature several hormonal disturbances, including hyperandrogenemia, insulin resistance (IR), and hyperinsulinemia. Insulin appears to disrupt all components of the hypothalamus-hypophysis-ovary axis, and ovarian tissue insulin resistance results in impaired metabolic signaling but intact mitogenic and steroidogenic activity, favoring hyperandrogenemia, which appears to be the main culprit of the clinical picture in PCOS. In turn, androgens may lead back to IR by increasing levels of free fatty acids and modifying muscle tissue composition and functionality, perpetuating this IR-hyperinsulinemia-hyperandrogenemia cycle. Nonobese women with PCOS showcase several differential features, with unique biochemical and hormonal profiles. Nevertheless, lean and obese patients have chronic inflammation mediating the long term cardiometabolic complications and comorbidities observed in women with PCOS, including dyslipidemia, metabolic syndrome, type 2 diabetes mellitus, and cardiovascular disease. Given these severe implications, it is important to thoroughly understand the pathophysiologic interconnections underlying PCOS, in order to provide superior therapeutic strategies and warrant improved quality of life to women with this syndrome.

Prevalence of cardiovascular disease and cancer during cross-sex hormone therapy in a large cohort of trans persons: a case-control study

OBJECTIVE

This study evaluated the short- and long-term cardiovascular- and cancer-related morbidities during cross-sex hormone therapy in a large sample of trans persons.

SUBJECTS AND METHODS

A specialist center cross-sectional study compared 214 trans women (male-to-female transsexual persons) and 138 trans men (female-to-male trans persons) with an age- and gender-matched control population (1-3 matching). The participants were on cross-sex hormone therapy for an average of 7.4 years. We assessed physical health and possible treatment-related adverse events using questionnaires.

RESULTS

Five percent of trans women experienced venous thrombosis and/or pulmonary embolism during hormone therapy. Five of these adverse events occurred during the first year of treatment, while another three occurred during sex reassignment surgery. Trans women experienced more myocardial infarctions than the control women (P=0.001), but a similar proportion compared with control men. The prevalence of cerebrovascular disease (CVD) was higher in trans women than in the control men (P=0.03). The rates of myocardial infarction and CVD in trans men were similar to the control male and female subjects. The prevalence of type 2 diabetes was higher in both trans men and women than in their respective controls, whereas the rates of cancer were similar compared with the control men and women.

CONCLUSION

Morbidity rate during cross-sex hormone therapy was relatively low, especially in trans men. We observed a higher prevalence of venous thrombosis, myocardial infarction, CVD, and type 2 diabetes in trans women than in the control population. Morbidity rates in trans men and controls were similar, with the exception of the increased prevalence of type 2 diabetes.

The role of androgen receptor activity mediated by the CAG repeat polymorphism in the pathogenesis of PCOS

Polycystic ovary syndrome (PCOS), one of the most common and complex endocrine disorders affecting up to 15 % of reproductive age women, is considered a predominantly hyperandrogenic syndrome according to the Androgen Excess Society. It is generally accepted that androgens determine the characteristic features of PCOS; in this context, a hyperactive androgen receptor (AR) at the levels of the GnRH pulse generator in the hypothalamus and at the granulosa cells in the ovary, skeletal muscle or adipocytes senses initially normal testosterone and dihydrotestosterone as biochemical hyperandrogenism and might be a crucial connection between the vicious circles of the PCOS pathogenesis. Polymorphism of the AR gene has been associated with different androgen pattern diseases. Several studies have demonstrated an association between AR with increased activity encoded by shorter CAG repeat polymorphism in the exon 1 of the AR gene and PCOS, although there are conflicting results in this field. The phenomenon is more complex because the AR activity is determined by the epigenetic effect of X chromosome inactivation (XCI). Moreover, we must evaluate the AR as a dynamic heterocomplex, with a large number of coactivators and corepressors that are essential to its function, thus mediating tissue-specific effects. In theory, any of these factors could modify the activity of AR, which likely explains the inconsistent results obtained when this activity was quantified by only the CAG polymorphism in PCOS.

Leydig cell hyperplasia and Leydig cell tumour in postmenopausal women: report of two cases

Leydig cell hyperplasia and Leydig cell tumours of the ovary are rare. We present two cases in which patients had increased blood levels of testosterone and frank hirsutism. Imaging showed minimal abnormalities. After adrenal disease had been ruled out, they underwent a bilateral oophorectomy. One case showed a Leydig cell hyperplasia, the other a Leydig cell tumour. An androgen producing tumour should be excluded in every woman with evidence of hirsutism or frank virilization and markedly elevated testosterone levels. Adrenal disease with androgen hypersecretion can be suspected by detailed clinical, laboratory and radiologic imaging. Although DHEAS has a good sensitivity in the detection of adrenal origin of hyperandrogenism (and hence a good negative predictive value) it is not specific (specificity ranging from 85 to 98%). Imaging of the ovaries can be helpful but does not rule out ovarian disease if normal. Indeed, diffuse stromal Leydig cell hyperplasia and Leydig cell tumours (usually small) may escape imaging and in some cases diagnosis can only be made on pathology. As these clinical entities represent a diagnostic and therapeutic challenge, oophorectomy should be considered in postmenopausal women with hirsutism and elevated testosterone levels, after the exclusion of adrenal causes. The procedure is relatively safe and effective. Follow-up remains indicated.

Insulin resistance and the polycystic ovary syndrome revisited: an update on mechanisms and implications

Polycystic ovary syndrome (PCOS) is now recognized as an important metabolic as well as reproductive disorder conferring substantially increased risk for type 2 diabetes. Affected women have marked insulin resistance, independent of obesity. This article summarizes the state of the science since we last reviewed the field in the Endocrine Reviews in 1997. There is general agreement that obese women with PCOS are insulin resistant, but some groups of lean affected women may have normal insulin sensitivity. There is a post-binding defect in receptor signaling likely due to increased receptor and insulin receptor substrate-1 serine phosphorylation that selectively affects metabolic but not mitogenic pathways in classic insulin target tissues and in the ovary. Constitutive activation of serine kinases in the MAPK-ERK pathway may contribute to resistance to insulin's metabolic actions in skeletal muscle. Insulin functions as a co-gonadotropin through its cognate receptor to modulate ovarian steroidogenesis. Genetic disruption of insulin signaling in the brain has indicated that this pathway is important for ovulation and body weight regulation. These insights have been directly translated into a novel therapy for PCOS with insulin-sensitizing drugs. Furthermore, androgens contribute to insulin resistance in PCOS. PCOS may also have developmental origins due to androgen exposure at critical periods or to intrauterine growth restriction. PCOS is a complex genetic disease, and first-degree relatives have reproductive and metabolic phenotypes. Several PCOS genetic susceptibility loci have been mapped and replicated. Some of the same susceptibility genes contribute to disease risk in Chinese and European PCOS populations, suggesting that PCOS is an ancient trait.

Androgens and skeletal muscle: cellular and molecular action mechanisms underlying the anabolic actions

Androgens increase both the size and strength of skeletal muscle via diverse mechanisms. The aim of this review is to discuss the different cellular targets of androgens in skeletal muscle as well as the respective androgen actions in these cells leading to changes in proliferation, myogenic differentiation, and protein metabolism. Androgens bind and activate a specific nuclear receptor which will directly affect the transcription of target genes. These genes encode muscle-specific transcription factors, enzymes, structural proteins, as well as microRNAs. In addition, anabolic action of androgens is partly established through crosstalk with other signaling molecules such as Akt, myostatin, IGF-I, and Notch. Finally, androgens may also exert non-genomic effects in muscle by increasing Ca(2+) uptake and modulating kinase activities. In conclusion, the anabolic effect of androgens on skeletal muscle is not only explained by activation of the myocyte androgen receptor but is also the combined result of many genomic and non-genomic actions.

Protein expression of PKCZ (Protein Kinase C Zeta), Munc18c, and Syntaxin-4 in the insulin pathway in endometria of patients with polycystic ovary syndrome (PCOS)

BACKGROUND

Polycystic Ovary Syndrome (PCOS) is an endocrine-metabolic disorder commonly associated with insulin resistance (IR). Previous studies indicate about the expression of molecules involved in the insulin pathway in endometria of women with PCOS-IR. Therefore, the aim of the present study was to evaluate the effect of insulin and testosterone in the expression of these proteins in the endometria and immortal endometrial stromal cell line (T-HESCs).

METHODS

We examined the protein levels of Munc18c, PKC zeta, phospho-PKC Zeta, and Syntaxin-4. Protein levels were assessed by Western Blot and/or immunohistochemistry in proliferative endometria (NPE = 6) and in PCOS endometria with insulin resistance (PCOSE-IR = 6). We also evaluated whether high concentrations of insulin (100 nM) and/or testosterone (100 nM), during a 24 h stimulatory period, affected the expression of these proteins in an immortal endometrial stromal cell line (T-HESCs). Once stimulated, proteins were extracted from cells and were assessed by Western Blot analysis. Immunocytochemistry was performed to detect AR in T-HESC cells.

RESULTS

Western Blot data showed decreased expression (p < 0,05) of Munc18c and phospho-PKC Zeta in PCOS-IR endometria (PCOSE-IR) with respect to the control (NPE). In the in vitro study, Western Blot analysis showed decreased levels of Munc18c, PKC Zeta and phospho-PKC Zeta with the different hormonal treatments when compared to the control condition (no hormonal stimulation) (p < 0,05). The AR was present in the endometrial stromal cell line (T-HESC).

CONCLUSION

The conditions of hyperinsulinism and hyperandrogenism present in PCOS-IR patients modulate the expression and/or phosphorylation of the proteins involved in the insulin pathway at the endometrial level. These data extend to the T-HESCs cells results, where insulin and testosterone exert an effect on both the expression and phosphorylation of proteins present in the pathway.

PI3K-Akt-mTOR and MAPK signaling pathways in polycystic ovarian syndrome, uterine leiomyomas and endometriosis: an update

PI3K-Akt-mTOR and MAP kinase are two important cell signaling pathways that are activated by steroid hormones and growth factors leading to cellular events including gene expression, cell proliferation and survival. These pathways are considered as an attractive target for the development of novel anticancer molecules, and selective inhibitors specifically targeting different components of these cascades have been developed. This review summarizes the current available knowledge on the PI3K-Akt-mTOR and MAPK pathways and their targeting in estrogen-dependent benign gynecological disorders viz. polycystic ovarian syndrome, uterine leiomyomas and endometriosis, which are a significant cause of high morbidity in women of reproductive age group. Increasing knowledge about the role of the two growth regulatory pathways in the pathogenesis of these disorders may give the opportunity to use specific signal transduction inhibitors for management of these patients in future.

Systematic review: association of polycystic ovary syndrome with metabolic syndrome and non-alcoholic fatty liver disease

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common disorder for women of child-bearing age and is associated with metabolic syndrome (MS).

AIM

To assess the literature for associations between polycystic ovary syndrome and non-alcoholic fatty liver disease (NAFLD).

METHODS

We performed a systematic review using PubMed-search for peer-reviewed articles related to polycystic ovary syndrome and NAFLD. Articles were summarised and grouped according to different sections defining interactions of polycystic ovary syndrome with metabolic syndrome and non-alcoholic fatty liver disease as well as risk factors, pathogenic pathways and treatment options.

RESULTS

Obesity is a common factor involved in both polycystic ovary syndrome and non-alcoholic fatty liver disease. Obesity causes non-alcoholic fatty liver disease and aggravates hirsutism and menstrual disorders in polycystic ovary syndrome. Insulin resistance, a hallmark of metabolic syndrome is observed in 50-80% of women with polycystic ovary syndrome and patients with non-alcoholic fatty liver disease. Recent findings suggest that women with polycystic ovary syndrome may be at risk for developing non-alcoholic fatty liver disease and conversely, non-alcoholic fatty liver disease may be a risk for polycystic ovary syndrome. Based on the association of polycystic ovary syndrome and other metabolic abnormalities, such as insulin resistance, hyperandrogenism, obesity and non-alcoholic fatty liver disease, the candidate genes have been speculated for polycystic ovary syndrome. Closer scrutiny of these genes placed most of their proteins at the crossroads of three highly inter-related conditions: metabolic syndrome, obesity and non-alcoholic fatty liver disease. In most studies, the prevalence of both polycystic ovary syndrome and non-alcoholic fatty liver disease rises proportionally to the degree of insulin resistance and increases in the mass of adipose tissue.

CONCLUSIONS

Non-alcoholic fatty liver disease is considered as the hepatic manifestation of metabolic syndrome. Similarly, it seems appropriate to consider polycystic ovary syndrome as the ovarian manifestation of metabolic syndrome. Both these conditions can co-exist and may respond to similar therapeutic strategies.

Insulin resistance is not conserved in myotubes established from women with PCOS

Background

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among premenopausal women, who often develop insulin resistance. We tested the hypothesis that insulin resistance in skeletal muscle of patients with polycystic ovary syndrome (PCOS) is an intrinsic defect, by investigating the metabolic characteristics and gene expression of in vitro differentiated myotubes established from well characterized PCOS subjects.

Methods

Using radiotracer techniques, RT-PCR and enzyme kinetic analysis we examined myotubes established from PCOS subjects with or without pioglitazone treatment, versus healthy control subjects who had been extensively metabolically characterized in vivo. Results Myotubes established from PCOS and matched control subjects comprehensively expressed all insulin-sensitive biomarkers; glucose uptake and oxidation, glycogen synthesis and lipid uptake. There were no significant differences between groups either at baseline or during acute insulin stimulation, although in vivo skeletal muscle was insulin resistant. In particular, we found no evidence for defects in insulin-stimulated glycogen synthase activity between groups. Myotubes established from PCOS patients with or without pioglitazone treatment also showed no significant differences between groups, neither at baseline nor during acute insulin stimulation, although in vivo pioglitazone treatment significantly improved insulin sensitivity. Consistently, the myotube cultures failed to show differences in mRNA levels of genes previously demonstrated to differ in PCOS patients with or without pioglitazone treatment (PLEK, SLC22A16, and TTBK).

Conclusion

These results suggest that the mechanisms governing insulin resistance in skeletal muscle of PCOS patients in vivo are not primary, but rather adaptive.

Trial Registration

ClinicalTrials.gov NCT00145340

Effects of metformin on the reproductive system of androgenized female rats

Metformin improved the glucose rate and the homeostasis model assessment-insulin resistance (HOMA-IR) index and caused partial reversion of ovaries and uterine morphology in female rats androgenized with testosterone.

Skeletal muscle insulin resistance in endocrine disease

We summarize the existing literature data concerning the involvement of skeletal muscle (SM) in whole body glucose homeostasis and the contribution of SM insulin resistance (IR) to the metabolic derangements observed in several endocrine disorders, including polycystic ovary syndrome (PCOS), adrenal disorders and thyroid function abnormalities. IR in PCOS is associated with a unique postbinding defect in insulin receptor signaling in general and in SM in particular, due to a complex interaction between genetic and environmental factors. Adrenal hormone excess is also associated with disrupted insulin action in peripheral tissues, such as SM. Furthermore, both hyper- and hypothyroidism are thought to be insulin resistant states, due to insulin receptor and postreceptor defects. Further studies are definitely needed in order to unravel the underlying pathogenetic mechanisms. In summary, the principal mechanisms involved in muscle IR in the endocrine diseases reviewed herein include abnormal phosphorylation of insulin signaling proteins, altered muscle fiber composition, reduced transcapillary insulin delivery, decreased glycogen synthesis, and impaired mitochondrial oxidative metabolism.

Targeting insulin sensitivity in the treatment of polycystic ovary syndrome

Targeting insulin resistance may result in a list of benefits for women with PCOS, including hormonal, metabolic and ovulatory (and fertility) improvements. The therapeutic strategy to treat PCOS should however depend on the clinical situation, the phenotype, the degree of androgen excess, age, the presence of infertility and the woman's desire to conceive, the presence of obesity and, finally, the spectrum of metabolic abnormalities and the need to treat or prevent long-term associated comorbidities. According to the needs, therapeutic options include, alone or in combination, lifestyle management, particularly in the presence of obesity, the use of insulin sensitizers, metformin and thiazolidinediones, antiandrogens or estro-progestins.

Lipid-induced mTOR activation in rat skeletal muscle reversed by exercise and 5'-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside

The serine/threonine protein kinase, mammalian target of rapamycin (mTOR) is regulated by insulin and nutrient availability and has been proposed to play a central role as a nutrient sensor in skeletal muscle. mTOR associates with its binding partners, raptor and rictor, to form two structurally and functionally distinct complexes, mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2) respectively. We have investigated the assembly of mTORC1/2 and the activation of their downstream substrates (i.e. Akt, S6K1) in response to known effectors of mTOR, excess lipid availability and AMP-activated protein kinase (AMPK) activation/exercise training in rat skeletal muscle. The in vivo formation of mTORC1 and 2 and the activation of their respective downstream substrates were increased in response to chronic (8 weeks) consumption of a high-fat diet. Diet-induced mTORC activation and skeletal muscle insulin resistance were reversed by 4 weeks of exercise training, which was associated with enhanced muscle AMPK activation. In order to determine whether AMPK activation reverses lipid-induced mTOR activation, L6 myotubes were exposed to 0.4 mM palmitate to activate mTORC1/2 in the absence or presence of 5'-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR). Palmitate exposure (4 h) increased insulin-stimulated S6K1 Thr389 phosphorylation by 60%, indicating activation of mTORC1. AMPK activation with 1 mM AICAR abolished lipid-induced mTOR activation in vitro. Our data implicates reductions in mTOR complex activation with the reversal of lipid-induced skeletal muscle insulin resistance in response to exercise training or AICAR and identifies mTOR as a potential target for the treatment of insulin resistance.