Antiandrogen treatment of polycystic ovary syndrome

Androgen signaling in adipose tissue, but less likely skeletal muscle, mediates development of metabolic traits in a PCOS mouse model

Polycystic ovary syndrome (PCOS) is a common, multifactorial disorder characterized by endocrine, reproductive, and metabolic dysfunction. As the etiology of PCOS is unknown, there is no cure and symptom-oriented treatments are suboptimal. Hyperandrogenism is a key diagnostic trait, and evidence suggests that androgen receptor (AR)-mediated actions are critical to PCOS pathogenesis. However, the key AR target sites involved remain to be fully defined. Adipocyte and muscle dysfunction are proposed as important sites involved in the manifestation of PCOS traits. We investigated the role of AR signaling in white adipose tissue (WAT), brown adipose tissue (BAT), and skeletal muscle in the development of PCOS in a hyperandrogenic PCOS mouse model. As expected, dihydrotestosterone (DHT) exposure induced key reproductive and metabolic PCOS traits in wild-type (WT) females. Transplantation of AR-insensitive (AR^-/-) WAT or BAT from AR knockout females (ARKO) into DHT-treated WT mice ameliorated some metabolic PCOS features, including increased body weight, adiposity, and adipocyte hypertrophy, but not reproductive PCOS traits. In contrast, DHT-treated ARKO female mice transplanted with AR-responsive (AR^+/+) WAT or BAT continued to resist developing PCOS traits. DHT-treated skeletal muscle-specific AR knockout females (SkMARKO) displayed a comparable phenotype with that of DHT-treated WT females, with full development of PCOS traits. Taken together, these findings infer that both WAT and BAT, but less likely skeletal muscle, are key sites of AR-mediated actions involved in the experimental pathogenesis of metabolic PCOS traits. These data further support targeting adipocyte AR-driven pathways in future research aimed at developing novel therapeutic interventions for PCOS.NEW & NOTEWORTHY Hyperandrogenism is a key feature in the pathogenesis of polycystic ovary syndrome (PCOS); however, the tissue sites of androgen receptor (AR) signaling are unclear. In this study, AR signaling in white and brown adipose tissue, but less likely in skeletal muscle, was found to be involved in the development of metabolic PCOS traits, highlighting the importance of androgen actions in adipose tissue and obesity in the manifestation of metabolic disturbances.

Impact of One-Week Administration of Dihydrotestosterone in Rat Anterior Pituitary Gland

Hyperandrogenism causes dysfunction of the hypothalamic-pituitary-gonadal (HPG) axis in reproductive women. In this study, we examined the effects of dihydrotestosterone (DHT) on characteristic changes in rat anterior pituitary gland samples. DHT was administered to ovary-intact 6-week postnatal female rats for 7 days, after which the anterior pituitary glands were examined and compared with those in control rats. Estrous cyclicity was not drastically disrupted by DHT treatment. Common gonadotropin α subunit (Cga), luteinizing hormone β subunit (Lhb), and follicle-stimulating hormone (FSH) β subunit (Fshb) gene expression levels were not modulated by DHT treatment, while prolactin (Prl) gene expression was significantly repressed by DHT. Gonadotropin-releasing hormone (GnRH) receptor (Gnrh-r) gene expression was significantly inhibited by DHT, whereas pituitary adenylate cyclase-activating polypeptide (PACAP) receptor (Pca1-r) gene expression was increased by DHT. Gene expression levels of the receptors encoded by thyrotropin-releasing hormone (Trh-r) and kisspeptin (Kiss1-r) genes were unchanged. Expression of inhibin α subunit (Inha) and activin βA subunits (Actba) within the pituitary was inhibited by DHT treatment, while activin B subunit (Actbb) and follistatin (Fst) gene expression was unchanged by DHT. In mouse pituitary gonadotroph LβT2 cells, DHT did not modulate the gene expression of Gnrh-r, but it inhibited the expression of Inha and Actba subunits within the LβT2 cells. In rat prolactin-producing GH3 cells, DHT did not modulate prolactin gene expression, but it increased Pac1-r gene expression. The present observations suggest that DHT directly or indirectly affects the anterior pituitary gland and induces characteristic changes in hormone-producing cells.

Lactic acid bacteria alleviate polycystic ovarian syndrome by regulating sex hormone related gut microbiota

Polycystic ovarian syndrome (PCOS) is a common endocrine disease across the world. Because gut microbiota play a key role in the pathogenesis of PCOS, probiotics may alleviate PCOS symptoms through the regulation of intestinal flora. The effects of 8 lactic acid bacterial strains on PCOS were investigated. Letrozole was used to produce a PCOS rat model and a 4-week-strain-intervention was performed. Diane-35, as a clinical PCOS treatment medicine, was effective in attenuating rats' reproductive disorders. Lactobacillus plantarum HL2 was protective against ovary pathological changes and restored luteinizing hormone, follicle stimulating hormone and testosterone levels. Bifidobacterium longum HB3 also alleviated ovary abnormalities and decreased testosterone levels. Administration of lactic acid bacteria up-regulated short-chain fatty acid levels. Based on 16S rRNA sequencing, lactic acid bacteria improved letrozole induced gut microbiota dysbiosis with different degrees. Akkermansia, Roseburia, Prevotella, Staphylococcus and Lactobacillus genera were correlated with sex hormone levels. Some of the sex hormone-related gut microbiota were restored by treatment with the strains. These results demonstrated that lactic acid bacteria alleviated PCOS in a rat model by regulating sex hormone related gut microbiota. Modifying gut microbiota by probiotic interventions may thus be a promising therapeutic option for PCOS.

Neurokinin 3 Receptor Antagonism Ameliorates Key Metabolic Features in a Hyperandrogenic PCOS Mouse Model

Polycystic ovary syndrome (PCOS) is a prevalent endocrine condition characterized by a range of endocrine, reproductive, and metabolic abnormalities. At present, management of women with PCOS is suboptimal as treatment is only symptomatic. Clinical and experimental advances in our understanding of PCOS etiology support a pivotal role for androgen neuroendocrine actions in PCOS pathogenesis. Hyperandrogenism is a key PCOS trait and androgen actions play a role in regulating the kisspeptin-/neurokinin B-/dynorphin (KNDy) system. This study aimed to investigate if targeted antagonism of neurokinin B signaling through the neurokinin 3 receptor (NK3R) would reverse PCOS traits in a dihydrotestosterone (DHT)-induced mouse model of PCOS. After 3 months, DHT exposure induced key reproductive PCOS traits of cycle irregularity and ovulatory dysfunction, and PCOS-like metabolic traits including increased body weight; white and brown fat pad weights; fasting serum triglyceride and glucose levels, and blood glucose incremental area under the curve. Treatment with a NK3R antagonist (MLE4901) did not impact the observed reproductive defects. In contrast, following NK3R antagonist treatment, PCOS-like females displayed decreased total body weight, adiposity, and adipocyte hypertrophy, but increased respiratory exchange ratio, suggesting NK3R antagonism altered the metabolic status of the PCOS-like females. NK3R antagonism did not improve circulating serum triglyceride or fasted glucose levels. Collectively, these findings demonstrate that NK3R antagonism may be beneficial in the treatment of adverse metabolic features associated with PCOS and support neuroendocrine targeting in the development of novel therapeutic strategies for PCOS.

Androgens impair β-cell function in a mouse model of polycystic ovary syndrome by activating endoplasmic reticulum stress

BACKGROUND

Androgens excess results in endoplasmic reticulum (ER) stress, which is an important cause of β cells dysfunction. Here, we investigated the molecular regulation of androgens excess, ER stress, and β-cell function in polycystic ovary syndrome (PCOS).

METHODS

PCOS mouse model was established by injection of DHEA. Primary cultured mouse islets were used to detect testosterone (TE)-induced ER stress. The response of ER stress, apoptosis, and hyperinsulinemia were analyzed in INS-1 cells with or without TE exposure. Androgen receptor (AR) antagonist and ER stress inhibitor treatment was performed to evaluate the role of TE in ER stress and proinsulin secretion of PCOS mice.

RESULTS

PCOS mice had higher ER stress in islets. TE exposure induced ER stress and apoptosis significantly through sustaining insulin overexpression in β cells, which in turn impaired proinsulin maturation and secretion. Blocking this process could significantly relieve ER stress and apoptosis and improve insulin homeostasis.

CONCLUSION

ER stress activated by androgens excess in PCOS contributes to β cell dysfunction and hyperinsulinemia.

Removal of DHT can relieve polycystic ovarian but not metabolic abnormalities in DHT-induced hyperandrogenism in mice

Polycystic ovary syndrome (PCOS) is an endocrine disorder with a high prevalence in women of childbearing age. To date, there is no method of efficiently diagnosing PCOS and curing it completely because its pathomechanism remains unclear. Here, we investigated whether metabolic abnormalities maintain the hyperandrogenism and PCOS-like ovaries and whether the symptoms induced by excess androgen are treatable. We ceased the abnormal dihydrotestosterone (DHT) stimulation to determine changes in PCOS-like mice. After ceasing DHT stimulation, the ovarian morphology and gene expression recovered from the DHT-stimulated status. However, after cessation of DHT stimulation, the hypertrophy of adipose tissues and hepatic steatosis were not significantly restored, and fat accumulation-related gene expression and serum metabolic markers in the mice were altered. These findings showed that the reproductive dysfunction was obviously relieved, but because the metabolic abnormalities were not relieved after the cessation of excess androgen for 30 days, it appears that the latter may not maintain the former.

Androgen Action in Adipose Tissue and the Brain are Key Mediators in the Development of PCOS Traits in a Mouse Model

Polycystic ovary syndrome (PCOS) is a complex disorder characterized by endocrine, reproductive, and metabolic abnormalities. Despite PCOS being the most common endocrinopathy affecting women of reproductive age, the etiology of PCOS is poorly understood, so there is no cure and symptomatic treatment is suboptimal. Hyperandrogenism is the most consistent feature observed in PCOS patients, and recently aberrant neuroendocrine signaling and adipose tissue function have been proposed as playing a role in the development of PCOS. To investigate the role of adipose tissue and the brain as key sites for androgen receptor (AR)-mediated development of PCOS, we combined a white and brown adipose and brain-specific AR knockout (AdBARKO) mouse model with a dihydrotestosterone (DHT)-induced mouse model of PCOS. As expected, in wildtype (WT) control females, DHT exposure induced the reproductive PCOS traits of cycle irregularity, ovulatory dysfunction, and reduced follicle health, whereas in AdBARKO females, DHT did not produce the reproductive features of PCOS. The metabolic PCOS characteristics of increased adiposity, adipocyte hypertrophy, and hepatic steatosis induced by DHT in WT females were not evident in DHT-treated AdBARKO females, which displayed normal white adipose tissue weight and no adipocyte hypertrophy or liver steatosis. Dihydrotestosterone treatment induced increased fasting glucose levels in both WT and AdBARKO females. These findings demonstrate that adipose tissue and the brain are key loci of androgen-mediated actions involved in the developmental origins of PCOS. These data support targeting adipocyte and neuroendocrine AR-driven pathways in the future development of novel therapeutic strategies for PCOS.

Evidence from animal models on the pathogenesis of PCOS

Polycystic ovarian syndrome (PCOS) is the most common endocrine condition in women, and is characterized by reproductive, endocrine and metabolic features. However, there is no simple unequivocal diagnostic test for PCOS, its etiology remains unknown and there is no cure. Hence, the management of PCOS is suboptimal as it relies on the ad hoc empirical management of its symptoms only. Decisive studies are required to unravel the origins of PCOS, but due to ethical and logistical reasons these are not possible in humans. Experimental animal models for PCOS have been established which have enhanced our understanding of the mechanisms underlying PCOS and propose novel mechanism-based therapies to treat the condition. This review examines the findings from various animal models to reveal the current knowledge of the mechanisms underpinning the development of PCOS, and also provides insights into the implications from these studies for improved clinical management of this disorder.

High level of C-type natriuretic peptide induced by hyperandrogen-mediated anovulation in polycystic ovary syndrome mice

Polycystic ovary syndrome (PCOS), which is characterized by hyperandrogenism, is a complex endocrinopathy that affects the fertility of 9-18% of reproductive-aged women. However, the exact mechanism of PCOS, especially hyperandrogen-induced anovulation, is largely unknown to date. Physiologically, the natriuretic peptide type C/natriuretic peptide receptor 2 (CNP/NPR2) system is essential for sustaining oocyte meiotic arrest until the preovulatory luteinizing hormone (LH) surge. We therefore hypothesized that the CNP/NPR2 system is also involved in PCOS and contributes to arresting oocyte meiosis and ovulation. Here, based on a dehydroepiandrosterone (DHEA)-induced PCOS-like mouse model, persistent high levels of CNP/NPR2 were detected in anovulation ovaries. Meanwhile, oocytes arrested at the germinal vesicle stage correlated with persistent high levels of androgen and estrogen. We further showed that ovulation failure in these mice could be a result of elevated Nppc/Npr2 gene transcription that was directly increased by androgen (AR) and estrogen (ER) receptor signaling. Consistent with this, anovulation was alleviated by administration of either exogenous human chorionic gonadotropin (hCG) or inhibitors of AR or ER to reduce the level of CNP/NPR2. Additionally, the CNP/NPR2 expression pattern in the anovulated follicles was, to some extent, consistent with the clinical expression in PCOS patients. Therefore, our study highlights the important role an overactive CNP/NPR2 system caused by hyperandrogenism in preventing oocytes from maturation and ovulation in PCOS mice. Our findings provide insight into potential mechanisms responsible for infertility in women with PCOS.

Neuroendocrine androgen action is a key extraovarian mediator in the development of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a complex hormonal disorder characterized by reproductive, endocrine, and metabolic abnormalities. As the origins of PCOS remain unknown, mechanism-based treatments are not feasible and current management relies on treatment of symptoms. Hyperandrogenism is the most consistent PCOS characteristic; however, it is unclear whether androgen excess, which is treatable, is a cause or a consequence of PCOS. As androgens mediate their actions via the androgen receptor (AR), we combined a mouse model of dihydrotestosterone (DHT)-induced PCOS with global and cell-specific AR-resistant (ARKO) mice to investigate the locus of androgen actions that mediate the development of the PCOS phenotype. Global loss of the AR reveals that AR signaling is required for all DHT-induced features of PCOS. Neuron-specific AR signaling was required for the development of dysfunctional ovulation, classic polycystic ovaries, reduced large antral follicle health, and several metabolic traits including obesity and dyslipidemia. In addition, ovariectomized ARKO hosts with wild-type ovary transplants displayed normal estrous cycles and corpora lutea, despite DHT treatment, implying extraovarian and not intraovarian AR actions are key loci of androgen action in generating the PCOS phenotype. These findings provide strong evidence that neuroendocrine genomic AR signaling is an important extraovarian mediator in the development of PCOS traits. Thus, targeting AR-driven mechanisms that initiate PCOS is a promising strategy for the development of novel treatments for PCOS.

Role of androgens in normal and pathological ovarian function

Androgens mediate their actions via the androgen receptor (AR), a member of the nuclear receptor superfamily. AR-mediated androgen action is essential in male reproductive development and function; however, only in the last decade has the suspected but unproven role for AR-mediated actions in female reproduction been firmly established. Deciphering the specific roles and precise pathways by which AR-mediated actions regulate ovarian function has been hindered by confusion on how to interpret results from pharmacological studies using androgens that can be converted into oestrogens, which exert actions via the oestrogen receptors. The generation and analysis of global and cell-specific femaleArknockout mouse models have deduced a role for AR-mediated actions in regulating ovarian function, maintaining female fertility, and have begun to unravel the mechanisms by which AR-mediated androgen actions regulate follicle health, development and ovulation. Furthermore, observational findings from human studies and animal models provide substantial evidence to support a role for AR-mediated effects not only in normal ovarian function but also in the development of the frequent ovarian pathological disorder, polycystic ovarian syndrome (PCOS). This review focuses on combining the findings from observational studies in humans, pharmacological studies and animal models to reveal the roles of AR-mediated actions in normal and pathological ovarian function. Together these findings will enable us to begin understanding the important roles of AR actions in the regulation of female fertility and ovarian ageing, as well as providing insights into the role of AR actions in the androgen-associated reproductive disorder PCOS.

Androgen receptor antagonists: a patent review (2008-2011)

INTRODUCTION

Androgen receptor (AR) antagonists are predominantly used as chemical castration to treat prostate cancer (i.e., in conjunction with androgen deprivation therapy (ADT)). Unfortunately, castration-resistant prostate cancer (CRPC) typically develops that is refractory to targeted therapy. Insights into CRPC biology have led to the emergence of a promising clinical candidate MDV3100 (1) and a resurgence in this field. A pipeline of preclinical competitive (C-terminally directed) antagonists was discovered using a variety of innovative screening paradigms. Some inhibit nuclear translocation, selectively downregulate or degrade AR (SARD), antagonize wild-type and escape mutant AR (pan-antagonists) and/or antagonize AR target organs in vivo. Separately, the N-terminal domain has emerged as a promising novel target for noncompetitive antagonists.

AREAS COVERED

AR antagonists whose patents published between 2008 and 2011 are reviewed. Antagonists are organized based on the screening paradigm reported as discussed above.

EXPERT OPINION

Novel mechanisms provide a more informed basis for selecting a competitive antagonist; however, high potency and favorable in vivo properties remain paramount. Noncompetitive antagonists have theoretical advantages suggestive of improved clinical efficacy, but no clinical proof of concept as of yet.

Effect of short-term standard therapeutic regimens on neuropeptide Y and adipose tissue hormones in overweight insulin-resistant women with polycystic ovary syndrome

AIM

The study was aimed at elucidating the influence of a 3-month treatment with routine therapeutic regimens--oral hormonal contraceptives (OHC) with antiandrogenic activity (a standard combination of ethynil estradiol 35 microg plus cyproterone acetate 2 mg) in combination with insulin sensitizing agents--metformin (Group I) and rosiglitazone (Group II) on adipose tissue hormones and hypothalamic neuropeptide Y (NPY) in women with polycystic ovary syndrome.

PATIENTS AND METHODS

The study included 66 overweight insulin resistant women with PCOS according to the recent ESHRE-ASRM criteria randomized into 2 age-matched therapeutic groups.

RESULTS

Significant decrease of leptin (P < 0.01; P = 0.001, resp.), resistin (P < 0.01; P < 0.01, resp.), tumour necrosis factor alpha (TNF alpha) (P = 0.001; P < 0.001, resp.), and NPY (P < 0.05; P < 0.001, resp.) was observed in both groups after treatment. These findings were in parallel with a significant decrease in the anthropometric parameters of body weight in the metformin group only. No significant changes in hormonal characteristics of the groups were found except for a significant decrease in androstenedione and DHEA-S (P < 0.05) in the metformin group and in 17-OH-progesterone (P < 0.05) in the rosiglitazone group. HDL-cholesterol rose and diastolic blood pressure fell significantly (P < 0.05) in the metformin group.

CONCLUSION

Our data suggest beneficial effects of the treatment on potential cardiovascular risk in insulin resistant PCOS women.

Retrospective observational study on the effects and tolerability of flutamide in a large population of patients with various kinds of hirsutism over a 15-year period

OBJECTIVE

The aim of the study was to evaluate the long-term effects and tolerability of flutamide (Flu) in hirsute women. To the best of our knowledge, this study represents the largest report, concerning the population studied and the duration of treatment, to evaluate Flu use in hirsutism treatment.

DESIGN, PATIENTS AND METHODS

Over a 15-year period spanning from January 1991 to January 2006, a total of 414 premenopausal women with hirsutism of different aetiopathogeneses received yearly reducing doses (250, 125 and 62.5 mg/day) of Flu alone or in combination with oral contraceptives for a period varying from at least 3 to 8 years and more. Clinical and endocrine evaluations were assessed half-yearly and yearly respectively in the first 3 years of the study, and yearly in the following years. Liver function evaluations were assessed quarterly.

RESULTS

Both the groups of patients under Flu therapy showed a marked decrease in hirsutism scores after 12 months compared with basal values. The maximum drug effect was observed after 2 years, and it was maintained during the following years of treatment. Androgens were strongly suppressed during treatment. During the first year of treatment, 6.0% of patients abandoned the study due to hepatic disorders related to the drug. During the following years with the lowest treatment regimen, none of the patients abandoned the study due to hepatic discomfort.

CONCLUSIONS

Flu is a satisfactory therapeutic regimen for any form of hirsutism in the long run. Moreover, the use of very low doses of Flu is associated with minimal side-effects and high compliance.

Androgen actions and the ovary

Although androgens and the androgen receptor (AR) have defining roles in male reproductive development and function, previously no role in female reproductive physiology beyond testosterone (T) as the precursor in estradiol (E(2)) biosynthesis was firmly established. Understanding the role and specific mechanisms of androgen action via the AR in the ovary has been limited by confusion on how to interpret results from pharmacological studies, because many androgens can be metabolized in vivo and in vitro to steroids that can also exert actions via the estrogen receptor (ESR). Recent genetic studies using mouse models with specific disruption of the Ar gene have highlighted the role that AR-mediated actions play in maintaining female fertility through key roles in the regulation of follicle health, development, and ovulation. Furthermore, these genetic studies have revealed that AR-mediated effects influence age-related female fertility, possibly via mechanisms acting predominantly at the hypothalamic-pituitary axis in a dose-dependent manner. This review focuses on combining the findings from pharmacological studies and novel genetic mouse models to unravel the roles of ovarian androgen actions in relation to female fertility and ovarian aging, as well as creating new insights into the role of androgens in androgen-associated reproductive disorders such as polycystic ovarian syndrome.

Female mice haploinsufficient for an inactivated androgen receptor (AR) exhibit age-dependent defects that resemble the AR null phenotype of dysfunctional late follicle development, ovulation, and fertility

The role of classical genomic androgen receptor (AR) mediated actions in female reproductive physiology remains unclear. Female mice homozygous for an in-frame deletion of exon 3 of the Ar (AR(-/-)) were subfertile, exhibiting delayed production of their first litter (AR(+/+) = 22 d vs. AR(-/-) = 61 d, P < 0.05) and producing 60% fewer pups/litter (AR(+/+): 8.1 +/- 0.4 vs. AR(-/-): 3.2 +/- 0.9, P < 0.01). Heterozygous females (AR(+/-)) exhibited an age-dependent 55% reduction (P < 0.01) in pups per litter, evident from 6 months of age (P < 0.05), compared with AR(+/+), indicating a significant gene dosage effect on female fertility. Ovulation was defective with a significant reduction in corpora lutea numbers (48-79%, P < 0.01) in 10- to 12- and 26-wk-old AR(+/-) and AR(-/-) females and a 57% reduction in oocytes recovered from naturally mated AR(-/-) females (AR(+/+): 9.8 +/- 1.0 vs. AR(-/-): 4.2 +/- 1.2, P < 0.01); however, early embryo development to the two-cell stage was unaltered. The delay in first litter, reduction in natural ovulation rate, and aromatase expression in AR(+/-) and AR(-/-) ovaries, coupled with the restored ovulation rate by gonadotropin hyperstimulation in AR(-/-) females, suggest aberrant gonadotropin regulation. A 2.7-fold increase (AR(+/+): 35.4 +/- 13.4 vs. AR(-/-): 93.9 +/- 6.1, P < 0.01) in morphologically unhealthy antral follicles demonstrated deficiencies in late follicular development, although growing follicle populations and growth rates were unaltered. This novel model reveals that classical genomic AR action is critical for normal ovarian function, although not for follicle depletion and that haploinsufficiency for an inactivated AR may contribute to a premature reduction in female fecundity.

Metformin and polycystic ovary syndrome

PURPOSE OF REVIEW

The aim of this article is to describe the role of insulin resistance in the etiology of polycystic ovary syndrome and to review the results of treatment with the insulin sensitizing drug metformin.

RECENT FINDINGS

Polycystic ovary syndrome is a heterogeneous combination of clinical, hormonal, and reproductive abnormalities associated with insulin resistance and increased cardiovascular risk factors. Reduction of hyperinsulinism and improvement of insulin sensitivity with metformin has been reported to ameliorate these abnormalities in many, but not all studies, with few adverse effects.

SUMMARY

Metformin may be the drug of first choice for most, if not all women with polycystic ovarian syndrome, either alone or in combination with other treatments. Further investigation is necessary to determine the optimal dose and duration of treatment necessary to maximize response.

Ovarian steroids: the good, the bad, and the signals that raise them

Ovarian steroid production and subsequent local steroid-mediated signaling are critical for normal ovarian processes, including follicle growth, oocyte maturation, and ovulation. In contrast, elevated steroidogenesis and/or increased steroid signaling in the ovary can lead to profound ovarian pathology, such as polycystic ovarian syndrome, the leading cause of infertility in reproductive age women. Through the use of several in vitro and animal models, great strides have been made toward characterizing the mechanisms regulating local steroid production and action in the ovary. Examples of this progress include insights into luteinizing hormone (LH)- and growth factor-mediated signaling, steroidogenic acute regulatory protein (StAR) activation, and both genomic and nongenomic steroid-mediated signaling in somatic and germ cells, respectively. The following review will address these advances, focusing on how this rapidly expanding knowledge base can be used to better understand female reproduction, and to further improve treatments for common diseases of infertility.

Obesity and androgens: facts and perspectives

OBJECTIVE

This review discusses androgen status in male and female obesity, according to their specific phenotype, and the main mechanisms responsible.

DESIGN

Published data in the literature of the last 20 years represented the basis of most of the data and concepts incorporated in the review.

RESULT(S)

Obesity is associated with profound alterations in androgen secretion, transport, metabolism, and action, according to a dichotomous behavior depending on sex. Obese men are characterized by a progressive decrease of testosterone levels with increasing body weight, whereas obese women, particularly those with the abdominal phenotype, tend to develop a condition of functional hyperandrogenism. Reduced sex hormone-binding globulin synthesis and circulating blood levels represent the sole common mechanism which is responsible in both sexes. Among other still partially undefined factors, mechanisms potentially responsible for the sex dichotomy in androgen levels involve specific alterations of gonadotropin secretion, estrogens, the hypothalamic-pituitary-adrenal axis, leptin, androgen receptors, specific steroidogenic enzymes in the peripheral tissues, and, possibly, ghrelin. In both sexes, androgens play an important role in determining the sex-dependent pattern of body fat distribution. Moreover there are theoretical possibilities that low testosterone in men and high free testosterone fraction in women may play a role in the development of the metabolic syndrome. This is exemplified by the well defined association between obesity and other features of the metabolic syndrome in women with polycystic ovary syndrome and in hypogonadal men. The effects of androgen and antiandrogens in obese men and women also represent arguments in favor of this association.

CONCLUSION(S)

Given the fundamental role of sex hormones in the regulation of body composition, fuel homeostasis, and reproduction in humans, more emphasis should be placed on the potential role of androgen dysregulation in the pathophysiology of different obesity phenotypes and the metabolic syndrome.

Fetal programming: prenatal testosterone treatment leads to follicular persistence/luteal defects; partial restoration of ovarian function by cyclic progesterone treatment

Prenatal testosterone (T) excess during midgestation leads to estrous cycle defects and polycystic ovaries in sheep. We hypothesized that follicular persistence causes polycystic ovaries and that cyclic progesterone (P) treatment would overcome follicular persistence and restore cyclicity. Twice-weekly blood samples for P measurements were taken from control (C; n = 16) and prenatally T-treated (T60; n = 14; 100 mg T, im, twice weekly from d 30-90 of gestation) Suffolk sheep starting before the onset of puberty and continuing through the second breeding season. A subset of C and T60 sheep were treated cyclically with a modified controlled internal drug-releasing device for 13-14 d every 17 d during the first anestrus (CP, 7; TP, 6). Transrectal ovarian ultrasonography was performed for 8 d in the first and 21 d in the second breeding season. Prenatal T excess reduced the number, but increased the duration of progestogenic cycles, reduced the proportion of ewes with normal cycles, increased the proportion of ewes with subluteal cycles, decreased the proportion of ewes with ovulatory cycles, induced the occurrence of persistent follicles, and reduced the number of corpora lutea in those that cycled. Cyclic P treatment in anestrus, which produced one third the P concentration seen during luteal phase of cycle, did not reduce the number of persistent follicles, but increased the number of progestogenic cycles while reducing their duration. These findings suggested that follicular persistence might contribute to the polycystic ovarian morphology. Cyclic P treatment was able to only partially restore follicular dynamics, but this may be related to the low replacement concentrations of P achieved.

Epidermal growth factor receptor signaling is required for normal ovarian steroidogenesis and oocyte maturation

The midcycle luteinizing hormone (LH) surge triggers several tightly linked ovarian processes, including steroidogenesis, oocyte maturation, and ovulation. We designed studies to determine whether epidermal growth factor receptor (EGFR)-mediated signaling might serve as a common regulator of these activities. Our results showed that EGF promoted steroidogenesis in two different in vitro models of oocyte-granulosa cell complexes. Inhibition of the EGFR kinase prevented EGF-induced steroidogenesis in these in vitro systems and blocked LH-induced steroidogenesis in intact follicles primed with pregnant mare serum gonadotropin. Similarly, inhibition of the EGFR kinase attenuated LH-induced steroidogenesis in MA-10 Leydig cells. Together, these results indicate that EGFR signaling is critical for normal gonadotropin-induced steroidogenesis in both male and female gonads. Interestingly, inhibition of metalloproteinase-mediated cleavage of membrane-bound EGF moieties abrogated LH-induced steroidogenesis in ovarian follicles but not MA-10 cells, suggesting that LH receptor signaling activates the EGFR by different mechanisms in these two models. Finally, steroids promoted oocyte maturation in several ovarian follicle models, doing so by signaling through classical steroid receptors. We present a model whereby steroid production may serve as one of many integrated signals triggered by EGFR signaling to promote oocyte maturation in gonadotropin-stimulated follicles.

Oocyte maturation: the coming of age of a germ cell

Normal female fertility relies on proper development of the oocyte. This growth culminates just prior to ovulation, when oocyte maturation occurs. Oocyte maturation refers to a release of meiotic arrest that allows oocytes to advance from prophase I to metaphase II of meiosis. This precisely regulated meiotic progression is essential for normal ovulation and subsequent fertilization, and involves changes in the delicate balance between factors promoting meiotic arrest and others that are stimulating maturation. Most of the inhibitory mechanisms appear to involve the upregulation of intracellular cyclic adenosine monophosphate levels. These processes may include direct transport of the nucleotide into oocytes via gap junctions, G protein-mediated stimulation of adenylyl cyclase, and inhibition of intracellular phosphodiesterases. In contrast, potential factors that play roles in triggering oocyte maturation include gonadotropins (e.g., follicle-stimulating factor and luteinizing hormone), growth factors (e.g., amphiregulin and epiregulin), sterols (e.g., follicular fluid-derived meiosis-activating sterol), and steroids (e.g., testosterone progesterone, and estradiol). Delineating the complex interactions between these positive and negative components is critical for determining the role that oocyte maturation plays in regulating follicle development and ovulation, and may lead to novel methods that can be used to modulate these processes in women with both normal and aberrant fertility.

Endocrine and metabolic effects of rosiglitazone in non-obese women with polycystic ovary disease

We hypothesized that the administration of rosiglitazone, an insulin-sensitizing agent of the thiazolidinedione class, would improve the ovulatory dysfunction, hirsutism, hyperandrogenemia, and hyperinsulinemia of polycystic ovary syndrome (PCOS) patients. Forty women with PCOS and impaired glucose tolerance test (IGT) were randomly assigned to the 8-month treatment with rosiglitazone at either 2 mg/day or 4 mg/day. We compared changes in ovulatory function, hirsutism, hormonal levels (total and free testosterone, estradiol, estrone, androstenedione, LH and FSH), and measures of glycemic parameters (fasting and post-challenge levels of glucose and insulin, HOMA-IR, hemoglobin A1c), between the study groups. The patients' baseline characteristics were similar across all treatment arms. Fifteen of 20 women in the 2 mg group and 19 of 20 women in the 4 mg group achieved normal glucose tolerance; 14 of 20 women in the 2 mg group and 17 of 20 women in the 4 mg group achieved ovulatory menses at the end of the study period. The decreases of free testosterone levels were better in the 4 mg group than the 2 mg rosiglitazone group (-1.89+/-0.35 pg/ml vs. -2.21+/-0.39 pg/ml; P<0.01). There were neither any serious adverse events nor any liver enzyme elevations in our study patients during the treatment period. This study demonstrated that rosiglitazone improves the ovulatory dysfunction, hirsutism, hyperandrogenemia, and insulin resistance of PCOS in a dose-related fashion, with minimal adverse effects. This drug may be a good choice for lifetime treatment of patients with PCOS, especially for the ones who failed to show satisfactory results in metformin therapy.

Medical treatment regimens of hirsutism

Hirsutism, which is a common clinical problem in women of reproductive age, is characterized by excessive growth of terminal hair in the androgen-sensitive skin regions. It is the result of either androgen excess or increased sensitivity of the hair follicles to normal levels of androgens. The management, which includes cosmetic measures and medical treatment, is far from satisfactory. Anti-androgen drugs play a key role in the treatment of hirsutism, but they have some side-effects which may result in cessation of the drug. On the other hand, anti-androgen treatment often needs to be continued for a long time. So, safe, inexpensive, and effective anti-androgen drugs are needed. Recently low-dose anti-androgen drugs have been shown to be effective in the maintenance of treatment. On the other hand, cyproterone acetate plus ethyniloestradiol and spironolactone, cyproterone acetate plus ethyniloestradiol and finasteride, and spironolactone and finasteride combinations have been used successfully in decreasing the hirsutism score. There are also some promising data regarding the effects of insulin sensitizers in the treatment of hirsutism, particularly in patients with polycystic ovarian syndrome. In the present review, the main features of anti-androgen drugs, new combined treatments, and insulin sensitizers in the treatment of hirsutism are discussed.

Neuroendocrine mechanisms of development of experimental hyperandrogen-induced anovulation

An experimental model of hyperandrogen-induced anovulatory infertility (s.c. implantation of Silastic capsules containing testosterone into adult female rats) was used to study morphological, hormonal, and biochemical measures characterizing the state of the hypothalamo-hypophyseal-ovarian system. Impairments in functional androgen metabolism in the hypothalamus were seen, with decreases in the Luliberin sensitivity of the hypophysis, changes in the structure of estral cycles, and morphological changes in the ovaries; these findings are evidence for neuroendocrine disturbances in the control of ovulation. Flutamide, an experimental antiandrogen, led to partial normalization of the hormonal, biochemical, and morphological characteristics, as well as to recovery of fertility in females with anovulatory infertility.

Steroids and oocyte maturation--a new look at an old story

Female fertility requires precise regulation of oocyte meiosis. Oocytes are arrested early in the meiotic cycle until just before ovulation, when ovarian factors trigger meiosis, or maturation, to continue. Although much has been learned about the late signaling events that accompany meiosis, until recently less was known about the early actions that initiate maturation. Studies using the well-characterized model of transcription-independent steroid-induced oocyte maturation in Xenopus laevis now show that steroid metabolism, classical steroid receptors, G protein-mediated signaling, and novel G protein-coupled receptors, all may play important roles in regulating meiosis. Furthermore, steroids appear to promote similar events in mammalian oocytes, implying a conserved mechanism of maturation in vertebrates. Interestingly, testosterone is a potent promoter of mammalian oocyte maturation, suggesting that androgen actions in the oocyte might be partially responsible for the polycystic ovarian phenotype and accompanying infertility associated with high androgen states such as polycystic ovarian syndrome or congenital adrenal hyperplasia. A detailed appreciation of the steroid-activated signaling pathways in frog and mammalian oocytes may therefore prove useful in understanding both normal and abnormal ovarian development in humans.

Androgens promote maturation and signaling in mouse oocytes independent of transcription: a release of inhibition model for mammalian oocyte meiosis

Normal fertility in females depends upon precise regulation of oocyte meiosis. Oocytes are arrested in prophase I of meiosis until just before ovulation, when meiosis, or maturation, is triggered to resume. Whereas sex steroids appear to promote maturation in fish and amphibians, the factors regulating mammalian oocyte maturation have remained obscure. We show here that, similar to lower vertebrates, steroids may play a role in promoting the release of meiotic inhibition in mammals. Specifically, testosterone induced maturation of mouse oocytes arrested in meiosis, as well as activation of MAPK and cyclin-dependent kinase 1 signaling. These responses appeared to be transcription independent and might involve signaling through classical androgen receptors expressed in the oocytes. Our results are the first to show that sex steroids can modulate meiosis in mammalian oocytes and suggest a model whereby dominant ovarian follicles in mammals may produce sufficient androgen and/or other steroids to overcome constitutive inhibitory signals and allow oocyte maturation and subsequent ovulation to occur.

Cyproterone acetate for hirsutism

BACKGROUND

Hirsutism is a distressing and relatively common endocrine problem in women which may prove difficult to manage. Cyproterone acetate, an anti-androgen, is frequently used to treat hirsutism, usually in combination with ethinyl estradiol.

OBJECTIVES

The objective of this review was to investigate the effectiveness of cyproterone acetate alone, or in combination with ethinyl estradiol, in reducing hair growth in women with hirsutism secondary to ovarian hyperandrogenism.

SEARCH STRATEGY

The Cochrane Menstrual Disorders and Subfertility Group trials register was searched (last search - 4 June 2002). The Cochrane Menstrual Disorders and Subfertility Group register is based on regular searches of MEDLINE (1966 to 2002), EMBASE (1980 to 2002), CINAHL (1982 to 2002), PsycINFO (1987 to 2002) and CENTRAL (Issue 2, 2002 of the Cochrane Library) the handsearching of several journals and conference proceedings, and searches of several key grey literature sources. All publications of randomised controlled trials of cyproterone acetate with or without estrogen versus placebo or other drug therapies for hirsutism were identified.

SELECTION CRITERIA

All randomised controlled studies comparing:- cyproterone acetate to placebo- cyproterone acetate with ethinyl estradiol to placebo- cyproterone acetate with ethinyl estradiol to cyproterone acetate alone- cyproterone acetate (with or without estradiol) to other medical therapies for treatment of hirsutism.

DATA COLLECTION AND ANALYSIS

Eleven studies were identified which fulfilled the inclusion criteria. Nine randomised studies were included in the review, and two were excluded because of insufficient information. Only one study had more than 100 women included in the analysis. The major outcomes included: subjective improvement in hirsutism, changes in Ferriman Gallwey scores, changes in linear hair growth and hair shaft diameter, alterations in endocrine parameters, side effects to treatment, withdrawals during therapy

MAIN RESULTS

There were no clinical trials comparing cyproterone acetate alone with placebo. There was one small study comparing cyproterone acetate in combination with ethinyl estradiol to placebo. In this study there was a significant subjective reduction in hair growth with cyproterone acetate therapy, although the confidence limits were large. There were no studies comparing cyproterone acetate alone with cyproterone acetate in combination with ethinyl estradiol to treat hirsutism. In studies where cyproterone acetate was compared to other drug modalities (ketoconazole, spironolactone, flutamide, finasteride, GnRH analogues) no difference in clinical outcome was noted. There were, however, endocrinological differences in androgen and estrogen levels between different drug therapies. There were insufficient data to assess differences in side effects between women treated with cyproterone acetate and other medical therapy.

REVIEWER'S CONCLUSIONS

Cyproterone acetate combined with estradiol results in a subjective improvement in hirsutism compared to placebo. Clinical differences in outcome between cyproterone acetate and other medical therapies were not demonstrated in the studies included in this review. This may be because of the small size of the studies, lack of standardized assessment and lack of objective determinants of improvement in hirsutism. The endocrinological effects of the different drug therapies reflect the mode of action. Larger carefully designed studies are needed to compare efficacy and safety profiles between drug therapies for hirsutism.

The risk of liver disorders in women prescribed cyproterone acetate in combination with ethinyloestradiol (Dianette): a nested case-control study using the GPRD

PURPOSE

To explore the risk of liver disorders associated with cyproterone acetate combined with ethinyloestradiol (CPA/EE). CPA/EE is licensed in the UK for the treatment of women with acne and hirsutism and is a treatment option for polycystic ovary syndrome (PCOS). It acts as a contraceptive also.

METHODS

Using the General Practice Research Database, we conducted a cohort analysis and case-control study in women aged 15-39 with acne, hirsutism or PCOS to estimate the risk of liver disorders associated with CPA/EE.

RESULTS

Compared with cases exposed to conventional combined oral contraceptives (COCs), the age-adjusted incidence rate ratio for liver disorders in women using CPA/EE was 1.7 (95% CI: 0.9, 3.4) and compared with no use it was 1.5 (95% CI: 0.8, 2.8). In the case-control study, the adjusted odds ratio (OR) for liver disorders in women exposed to CPA/EE was 1.6 (95% CI: 0.7, 3.5) and 0.8 (95% CI: 0.5, 1.3) for exposure to conventional COCs, compared with no use. The risk of liver disorders in women prescribed CPA/EE was not significantly greater than that in women prescribed conventional COCs (OR: 2.1 [95% CI: 0.9, 4.8]).

CONCLUSION

Our results do not indicate an increased risk for liver disorders associated with CPA/EE use in women with acne, hirsutism or PCOS after adjusting for potential confounding. This may be due to lack of statistical power.

Obesity and the polycystic ovary syndrome

The polycystic ovary syndrome (PCOS) is a condition characterized by hyperandrogenism and chronic oligo-anovulation. However, many features of the metabolic syndrome are inconsistently present in the majority of women with PCOS. Approximately 50% of PCOS women are overweight or obese and most of them have the abdominal phenotype. Obesity may play a pathogenetic role in the development of the syndrome in susceptible individuals. In fact, insulin possesses true gonadotrophic function and an increased insulin availability at the level of ovarian tissue may favour excess androgen synthesis. Obesity, particularly the abdominal phenotype, may be partly responsible for insulin resistance and associated hyperinsulinemia in women with PCOS. Therefore, obesity-related hyperinsulinemia may play a key role in favouring hyperandrogenism in these women. Other factors such as increased estrogen production rate, increased activity of the opioid system and of the hypothalamic-pituitary-adrenal axis, decreased sex hormone binding globulin synthesis and, possibly, high dietary lipid intake, may be additional mechanisms by which obesity favours the development of hyperandrogenism in PCOS. Irrespective of the pathogenetic mechanism involved, obese PCOS women have more severe hyperandrogenism and related clinical features (such as hirsutism, menstrual abnormalities and anovulation) than normal-weight PCOS women. This picture tends to be more pronounced in obese PCOS women with the abdominal phenotype. Body weight loss is associated with beneficial effects on hormones, metabolism and clinical features. A further clinical and endocrinological improvement can also be achieved by adding insulin-sensitizing agents and/or antiandrogens to weight reduction programmes. These obviously emphasize the role of obesity in the pathophysiology of PCOS.