Exaggerated 17-hydroxyprogesterone response to intravenous infusions of recombinant human LH in women with polycystic ovary syndrome

Evaluation of the correlation between insulin like factor 3, polycystic ovary syndrome, and ovarian maldescent

The aim of this study was to investigate a proposed correlation between the incidentally discovered undescended ovaries and their confirmed diagnosis as a polycystic ovary disease (PCOD) for all cases included, and to evaluate the role of estimated insulin like factor 3 (INSL3) circulating level in the pathogenesis of both abnormal findings. The study group (A) comprised 35 women whose ovaries had been incidentally found to be undescended during the routine laparoscopy for infertility causes, and all had been diagnosed as PCOD. The control category included two subgroups; subgroup (B) included 35 women group, diagnosed as PCOD but with normally allocated ovaries in the true pelvis, and subgroup (C) included 35 healthy women with regular menses and no signs of hyperandrogenism. Correlations between the level of INSL3 and other PCOD relevant biochemical tests: [e.g. BMI, waist-to-hip ratio (WHR), LH, FSH, androstendione (A), total and free testosterone (T & Ft), DHEA-S, and SHBG] had been also investigated. INSL3 levels were significantly higher in PCOD groups (A) and (B) compared to the healthy fertile control subgroup (C) (80.5 ± 29.4, 65.11 ± 15.6, and 41.11 ± 10.2 pg/mL, respectively), and was highest in group (A). Moreover, we identified a strong correlation between INSL3 and androstenedione (r = 0.42, p = 0.0012), and free (r = 0.42, p = .0123) and total testosterone (r = 0.41, p = .004) in the PCOD (A) and (B) subgroup compared to the levels in subgroup (C). LH was significantly higher in all PCOD women in groups (A&B) (12. 3 ± 3.4, and 11.2 ± 1.4 mIU/L, respectively) compared to those in group (A) (5.7 ± 2.5 mIU/L), with a fair correlation with INSL3. However, there was no statistically significant correlation between INSL3 and FSH, DHEA-S, glucose, basal insulin concentration or HOMA-IR in all PCOD women. The strong positive correlation between INSL3, and high ovarian androgens levels in all PCOD women, which appeared clearly in undescended polycystic ovaries could support the proposed syndrome hypothesis between those abnormal findings.

The Pathogenesis of Polycystic Ovary Syndrome (PCOS): The Hypothesis of PCOS as Functional Ovarian Hyperandrogenism Revisited

Polycystic ovary syndrome (PCOS) was hypothesized to result from functional ovarian hyperandrogenism (FOH) due to dysregulation of androgen secretion in 1989-1995. Subsequent studies have supported and amplified this hypothesis. When defined as otherwise unexplained hyperandrogenic oligoanovulation, two-thirds of PCOS cases have functionally typical FOH, characterized by 17-hydroxyprogesterone hyperresponsiveness to gonadotropin stimulation. Two-thirds of the remaining PCOS have FOH detectable by testosterone elevation after suppression of adrenal androgen production. About 3% of PCOS have a related isolated functional adrenal hyperandrogenism. The remaining PCOS cases are mild and lack evidence of steroid secretory abnormalities; most of these are obese, which we postulate to account for their atypical PCOS. Approximately half of normal women with polycystic ovarian morphology (PCOM) have subclinical FOH-related steroidogenic defects. Theca cells from polycystic ovaries of classic PCOS patients in long-term culture have an intrinsic steroidogenic dysregulation that can account for the steroidogenic abnormalities typical of FOH. These cells overexpress most steroidogenic enzymes, particularly cytochrome P450c17. Overexpression of a protein identified by genome-wide association screening, differentially expressed in normal and neoplastic development 1A.V2, in normal theca cells has reproduced this PCOS phenotype in vitro. A metabolic syndrome of obesity-related and/or intrinsic insulin resistance occurs in about half of PCOS patients, and the compensatory hyperinsulinism has tissue-selective effects, which include aggravation of hyperandrogenism. PCOS seems to arise as a complex trait that results from the interaction of diverse genetic and environmental factors. Heritable factors include PCOM, hyperandrogenemia, insulin resistance, and insulin secretory defects. Environmental factors include prenatal androgen exposure and poor fetal growth, whereas acquired obesity is a major postnatal factor. The variety of pathways involved and lack of a common thread attests to the multifactorial nature and heterogeneity of the syndrome. Further research into the fundamental basis of the disorder will be necessary to optimally correct androgen levels, ovulation, and metabolic homeostasis.

Characterization of persistent follicles induced by prolonged treatment with progesterone in dairy cows: an experimental model for the study of ovarian follicular cysts

Cystic ovarian disease (COD) is a major factor contributing to poor reproductive efficiency of lactating dairy cows. The objective of the present study was to analyze the endocrine profile, growth dynamics, and histologic characteristics of persistent ovarian follicles-cysts developing in response to long-term administration of intermediate levels of progesterone. To this end, after synchronization of cows, a low dose of progesterone was administered for 5, 10, and 15 days after the expected day of ovulation in treated cows (groups P5, P10, and P15, respectively), using an intravaginal progesterone-releasing device. A significant increase in diameter was detected on Day 11 of progesterone treatment and thereafter (P < 0.05), and at Day 15 of persistence, the diameter of the persistent follicle reached a mean of 23 ± 0.6 mm. Microscopically, the persistent follicles had a complete granulosa, an intensely vascularized theca interna, and a collagenous theca externa layer. Temporal changes in the serum concentrations of estradiol, progesterone, and FSH were detected (effects of time, P < 0.01). Progesterone treatment completely inhibited the LH preovulatory surge in treated cows and affected the basal concentration of LH. The pulse frequency remained high at 5 and 10 days of persistence and declined (P < 0.05) after 15 days of persistence. The LH pulse concentration and pulse amplitude had a significant reduction (P < 0.05) during follicular persistence. Changes in the serum levels of estradiol, progesterone, 17-hydroxyprogesterone, and testosterone in serum and follicular fluid were also observed. In serum, estradiol increased gradually from proestrus to Day 10 of follicular persistence (P < 0.05), progesterone showed an increase (P < 0.05) at Day 5 of follicular persistence, 17-hydroxyprogesterone showed a significant decrease at 5 days of follicular persistence in relation to proestrus, and testosterone showed a significant increase (P < 0.05) from proestrus and Day 5 of persistence through Day 15 of follicular persistence. Correlation between serum and follicular fluid steroid concentrations was significant for testosterone (P < 0.0001) and not significant for estradiol and progesterone. These findings indicate that ovarian cysts in COD are similar in many ways to the persistent follicles induced by progesterone, with an analogous hormonal and morphologic context, thus confirming a local role of subluteal levels of progesterone in COD pathogenesis and in the regulatory mechanisms of the ovarian function.

Altered gene expression profile in cumulus cells of mature MII oocytes from patients with polycystic ovary syndrome

STUDY QUESTION

Oocyte developmental competence is altered in patients with polycystic ovary syndrome (PCOS); is gene expression in cumulus cells (CCs) from mature metaphase II oocytes of patients with PCOS altered as well?

SUMMARY ANSWER

Compared with CCs from non-PCOS patients, the gene expression profile of CCs isolated from mature oocytes of patients with PCOS present alterations that could explain the abnormal folliculogenesis and reduced oocyte competence in such patients.

WHAT IS KNOWN ALREADY

Abnormal mRNA expression of several members of the insulin-like growth factor (IGF) family in CCs from PCOS patients was previously reported. Moreover, the whole transcriptome has been investigated in cultured CCs from PCOS patients.

STUDY DESIGN, SIZE AND DURATION

This retrospective study included six PCOS patients diagnosed following the Rotterdam Criteria and six non-PCOS patients who all underwent ICSI for male infertility in the assisted reproduction technique (ART) Department of Montpellier University Hospital, between 2009 and 2011.

PARTICIPANTS/MATERIALS, SETTING AND METHODS

CCs from PCOS and non-PCOS patients who underwent controlled ovarian stimulation (COS) were isolated mechanically before ICSI. Gene expression profiles were analysed using the microarray technology and the Significance Analysis of Microarray was applied to compare the expression profiles of CCs from PCOS and non-PCOS patients.

MAIN RESULTS

The gene expression profile of CCs from patients with PCOS was significantly different from that of CCs from non-PCOS patients. Specifically, CCs from women with PCOS were characterized by abnormal expression of many growth factors, including members of the epidermal growth factor-like (EGFR, EREG and AREG) and IGF-like families (IGF1R, IGF2R, IGF2BP2 and IGFBP2), that are known to play a role in oocyte competence. In addition, mRNA transcripts of factors involved in steroid metabolism, such as CYP11A1, CYP1B1, CYP19A1 and CYP2B7P1, were deregulated in PCOS CCs, and this could explain the abnormal steroidogenesis observed in these women. Functional annotation of the differentially expressed genes suggests that defects in the transforming growth factor β and estrogen receptors signalling cascades may contribute to the reduced oocyte developmental competence in patients with PCOS.

LIMITATIONS AND REASONS FOR CAUTION

Owing to the strict selection criteria (similar age, weight and reasons for ART), this study included a small sample size (six cases and six controls), and thus, further investigations using a large cohort of patients are needed to confirm these results.

WIDER IMPLICATIONS OF THE FINDINGS

This study opens a new perspective for understanding the pathogenesis of PCOS.

STUDY FUNDING/COMPETING INTERESTS

This work was partially supported by a grant from the Ferring Pharmaceutical. The authors of the study have no competing interests to report.

TRIAL REGISTRATION NUMBER

Not applicable.

Basal insulin-like factor 3 levels predict functional ovarian hyperandrogenism in the polycystic ovary syndrome

AIM

The aims of the study were to understand the association between insulin-like factor 3 (INSL3) and functional ovarian hyperandrogenism (FOH) in PCOS and the regulatory role played by LH.

SUBJECTS AND METHODS

Fifteen PCOS women were classified as FOH (FOH-PCOS, no.=8) and non-FOH (NFOH-PCOS, no.=7) according to the response of 17OH-progesterone to buserelin (a GnRH analogue) with respect to 15 controls. FOH-PCOS and NFOH-PCOS were compared for basal INSL3 levels. In addition, the effect of buserelin on INSL3 concentrations and the relationship between basal and buserelin-stimulated LH and 17OH-progesterone and INSL3 were evaluated.

RESULTS

Basal INSL3 levels were higher in FOH-PCOS than NFOH-PCOS (p=0.001) and controls (p=0.001), whereas they did not differ between NFOHPCOS and controls. In addition, FOH-PCOS had a higher response of LH to buserelin with respect to NFOH-PCOS. Within all PCOS women the levels of INSL3 positively correlated with free testosterone (p=0.022) and negatively with SHBG (r= p=0.031). Moreover, positive correlations with the absolute increase of 17OH-progesterone (p<0.001) and with the LH area under the curve (p=0.001) after buserelin administration were found. In the multiple regression analysis INSL3 persisted significantly correlated only with 17OH-progesterone response to buserelin. Finally, INSL3 was not significantly modified after buserelin administration either in FOHPCOS or in NFOH-PCOS.

CONCLUSIONS

These data suggest that INSL3 is related to FOH in PCOS women, but this association seems not to be mediated by LH, further reinforcing the concept that a pathophysiological heterogeneity for ovarian hyperandrogenism in PCOS exists.

Clinical evidence for predominance of delta-5 steroid production in women with polycystic ovary syndrome

CONTEXT

In women with polycystic ovary syndrome (PCOS), the basis for ovarian androgen overproduction involves an overall increase of steroidogenesis, notably in the delta-4 pathway. However, in vitro studies have suggested that excessive androgen production occurs predominantly through the delta-5 pathway.

OBJECTIVE

This study was performed to assess androgen dose-responses after human chorionic gonadotropin (hCG) stimulation in PCOS and normal women.

DESIGN

We conducted a prospective study to compare androgen production after iv hCG in PCOS and normal women.

SETTING

The study was conducted in a General Clinical Research Center in an academic medical center.

PARTICIPANTS

Women with PCOS (age, 18-37 yr; n = 10) and normal ovulatory controls (age, 18-37 yr; n = 11) were recruited.

INTERVENTIONS

For dose-response studies, blood samples were obtained before and at 0.5, 24, and 48 h after iv recombinant hCG (1, 10, 25, 100, and 250 μg). A subset of subjects underwent frequent blood sampling over 24 h after iv injection of 25 μg of recombinant hCG.

MAIN OUTCOME MEASURE(S)

We measured basal and stimulated serum 17-hydroxyprogesterone (17-OHP), androstenedione (A), testosterone (T), dehydroepiandrosterone, estradiol, and progesterone responses after hCG administration.

RESULTS

In PCOS women, maximal A and T production was observed at the lowest doses of hCG, whereas responses were minimal in normal women. Incremental responses of 17-OHP, estradiol, and progesterone were greater in PCOS compared to normal women.

CONCLUSION

In PCOS women, maximal A and T responses to hCG relative to those of 17-OHP are consistent with ovarian androgen overproduction via the delta-5 pathway.

Evidence that obesity and androgens have independent and opposing effects on gonadotropin production from puberty to maturity

Optimal fat mass is necessary for normal gonadotropin levels in adults, and both undernutrition and overnutrition suppress gonadotropins: thus, the gonadotropin response to relative adipose mass is biphasic. Adult obesity is associated with blunted luteinizing hormone (LH) pulse amplitude that is partially attributable to increased LH clearance rate. Testosterone appears to have a biphasic effect on gonadotropin production in females. Moderate elevations of testosterone appear to stimulate LH production at both the hypothalamic and pituitary level, while very high levels of testosterone suppress LH. Thus, obesity per se appears to suppress gonadotropin production, and moderate hyperandrogenemia in women appears to stimulate LH. The ordinary hypergonadotropic hyperandrogenism of obese women appears to be an exception to this model because it is usually due to polycystic ovary syndrome (PCOS), a condition in which intrinsic functional ovarian hyperandrogenism and excess adiposity share a common origin that involves insulin-resistant hyperinsulinemia. LH elevation seems to be secondary to hyperandrogenemia and is absent in the most obese cases. Overweight early pubertal girls have significant blunting of sleep-related LH production, which is the first hormonal change of puberty. The data are compatible with the possibility that excess adiposity may paradoxically subtly suppress hypothalamic-pituitary-gonadal function in early puberty although it is known to contribute to the early onset of puberty.

Association of polycystic ovary syndrome with cardiovascular risk factors

BACKGROUND

Polycystic ovary syndrome (PCOS), also clinically known as Stein-Leventhal syndrome, is an endocrine disorder that affects 5-10% of women.

OBJECTIVE

To evaluate the risk factors for developing early onset of cardiovascular disease (CVD) in young patients with PCOS from our local population.

DESIGN

Case-control study.

METHODS

Fifty women with PCOS selected by history and transvaginal ultrasounds and 30 age-matched healthy women (controls). The case subjects and controls were further divided into two age categories comprising of equal number of subjects, of 20-29 and 30-39 years of age. The subjects underwent a detailed medical history, general physical examination, systolic (SBP) and diastolic blood pressures (DBP). Fasting blood samples were analyzed for glucose, insulin, triacylglycerides (TAG), total cholesterol, high density lipoprotein-C (HDL-C), low density lipoprotein-C (LDL-C), follicle-stimulating hormone (FSH), and luteinizing hormone (LH).

RESULTS

Women with the PCOS had significantly higher mean arterial pressure (MAP), serum TAG, LDL-C, insulin, and LH levels when compared with the age-matched control subjects. No significant differences were observed between serum cholesterol, glucose, and FSH levels between cases and controls. However, no marked differences were observed in biochemical parameters between the two age groups of PCOS patients.

CONCLUSIONS

Younger women with PCOS are equally at risk of developing CVD as older women.

Assessment of theca cell function prior to controlled ovarian stimulation: the predictive value of serum basal/stimulated steroid levels

BACKGROUND

Serum androgen levels correlate with ovarian sensitivity to follicle-stimulating hormone (FSH) but in practice, standard baseline serum testosterone (T) levels prior to in-vitro fertilization (IVF) may not be the most appropriate marker for determination.

METHODS

Infertile women enrolled in an IVF programme were included in this study. Serum T and Delta4-androstenedione (A), and the androgen precursor 17-hydroxyprogesterone (17-OHP) were measured before and 24 h after a gonadotrophin-releasing hormone agonist stimulation test (GAST). An early follicular phase antral follicle count (AFC) was also performed. Patients were subsequently enrolled in a long gonadotrophin-releasing hormone agonist protocol with a standard FSH dose (150 IU) for 7 days to assess the association between androgen levels and ovarian responsiveness to FSH.

RESULTS

The GAST elicited a significant increase in serum androgen levels that was well correlated with AFC. 17-OHP showed the greatest response to GAST and strongest correlation with AFC. The 17-OHP response to GAST differentiated patients with high ovarian reserve (OR) from those with low or normal OR as assessed by AFC, whereas only the estradiol response could differentiate those with low AFC. GAST-stimulated serum levels of 17-OHP were also correlated with ovarian response to FSH. Using receiver operating characteristic curve analysis, stimulated 17-OHP levels were predictive of the ovarian response to controlled ovarian stimulation, with similar power to that observed with AFC but lower power than with anti-Müllerian hormone.

CONCLUSIONS

Serum androgen levels following GAST are correlated with AFC and ovarian response to FSH. Serum T is a less sensitive marker of theca cell function than 17-OHP.

Characterization of functionally typical and atypical types of polycystic ovary syndrome

CONTEXT

The typical polycystic ovary syndrome (PCOS) phenotype includes 17-hydroxyprogesterone (17OHP) hyperresponsiveness to GnRH agonist (GnRHag) testing. Functionally atypical PCOS lacks this feature.

OBJECTIVE

The hypothesis was tested that the typical PCOS ovarian dysfunction results from intrinsically increased sensitivity to LH/human chorionic gonadotropin (hCG) due to a flaw in FSH action. PARTICIPANTS/DESIGN/INTERVENTIONS/MAIN OUTCOME MEASURES: After phenotyping a cohort of 60 women, steroid and inhibin-B responses to gonadotropins were evaluated in representative typical (n = 7) and atypical (n = 5) PCOS and healthy controls (n = 8). Submaximal hCG testing before and after an FSH test dose was performed in random order before and after prolonged ovarian suppression by depot GnRHag.

SETTING

The study was performed at a Clinical Research Center.

RESULTS

Of our PCOS cohort, 68% were the typical type. Typical PCOS had 17OHP hyperresponsiveness and, unlike controls, significant androgen and estradiol responses to hCG. FSH increased inhibin-B and did not inhibit free testosterone or enhance estradiol responsiveness to hCG, all unlike controls. After ovarian suppression, 17OHP, androstenedione, and inhibin-B responsiveness to gonadotropin testing persisted. Atypical PCOS had significantly higher body mass index but lower ovarian volume and plasma free testosterone than typical PCOS. Steroid responses to hCG were insignificant and similar to controls. FSH suppressed free testosterone but stimulated inhibin-B. The estradiol level after combined hCG-FSH was subnormal. Free testosterone was less GnRHag suppressible than in typical PCOS.

CONCLUSIONS

Typical PCOS is characterized by intrinsic ovarian hypersensitivity to hCG to which excessive paracrine FSH signaling via inhibin-B may contribute. Atypical PCOS is due to a unique type of ovarian dysfunction that is relatively gonadotropin hyposensitive.

[Serum inhibin B in polycystic ovary syndrome as a potential marker of ovarian dysfunction]

INTRODUCTION

Polycystic ovary syndrome (PCOS) is one of the most common causes of anovulation, infertility and hyperandrogenism, and the prevalence of this condition in women of reproductive is 5-10%. The growth of early ovarian antral follicles is arrested and dominant follicle selection is disturbed in this syndrome.

OBJECTIVE

The aim of this study is to investigate whether inhibin B serum concentrations represent the extent of ovarian abnormalities in patients with PCOS.

METHOD

Inhibin B serum concentrations on the third day of spontaneous menstrual cycle and other endocrine characteristics were compared between 20 patients with PCOS and 19 healthy women in the control group.

RESULTS

Inhibin B concentrations were not significantly different between women with PCOS and women in the control group. In patients with PCOS there was statistically significant correlation between serum inhibin B and LH (r = 0.514; p = 0.021).There were no positive correlations between inhibin B and others endocrine parameters in patients with PCOS (FSH, E2,T, androstenedione).

CONCLUSION

Inhibin B serum concentrations on the third day of spontaneous menstrual cycle in women with PCOS are not different from the concentrations in healthy women. Serum Inhibin B levels in patients with PCOS are only slightly correlated with the endocrine markers of the disease so it could not represent the magnitude of ovarian dysfunction in this syndrome.

17-hydroxyprogesterone responses to gonadotropin-releasing hormone disclose distinct phenotypes of functional ovarian hyperandrogenism and polycystic ovary syndrome

CONTEXT

The exaggerated 17-hydroxyprogesterone response to GnRH agonists, which reflects functional ovarian hyperandrogenism (FOH), is believed to be the prominent abnormality in women with polycystic ovary syndrome (PCOS).

OBJECTIVE

Our objectives were to quantify the prevalence of PCOS with FOH and to evaluate whether the presence of FOH may distinguish different clinical and biochemical phenotypes.

DESIGN, SETTING, AND PARTICIPANTS

We conducted an observational study at an academic hospital that included 148 PCOS women and 22 healthy age-matched normal-weight control women.

MAIN OUTCOME MEASURES

A hormone profile was taken at baseline and in response to (1-24)ACTH and to a GnRH agonist, buserelin, administered during dexamethasone suppression.

RESULTS

Based on the data obtained in the control subjects, the PCOS patients were divided into two groups, one with a normal (NR-PCOS, n = 78) and one with a high 17-hydroxyprogesterone response (HR-PCOS, n = 70) to buserelin. The two groups of PCOS subjects had similar anthropometric parameters and clinical signs of hyperandrogenism. Age and body weight at menarche were significantly lower and higher, respectively, in the HR-PCOS group than the NR-PCOS group. Moreover, the HR-PCOS group had higher basal testosterone (P < 0.001), free androgen index (P < 0.01), 17-hydroxyprogesterone (P < 0.05), estrogens (P < 0.05), area under the curve for insulin (insulin(AUC)) (P < 0.05), and C-peptide(AUC) (P < 0.01) and lower insulin sensitivity (as composite insulin sensitivity index) (P < 0.05) than the NR-PCOS group. The response of 17-hydroxyprogesterone to (1-24)ACTH (as percent variation) was lower in the HR-PCOS group with respect to the NR-PCOS group (P < 0.05), whereas the response of cortisol, androstenedione, and dehydroepiandrosterone was similar. Finally, the HR-PCOS group had lower percent suppression of androstenedione (P < 0.001) and 17-hydoxyprogesterone (P < 0.05) to dexamethasone. In a multiple regression model applied in all PCOS women, insulin(AUC) but not androgens or markers of insulin resistance predicted the 17-hydroxyprogesterone response to buserelin to a highly significant extent (t = 3.269; P < 0.01).

CONCLUSIONS

This study indicates that the paradigm that FOH is a specific feature of the PCOS status can no longer be sustained. We have shown that women with an exaggerated 17-hydroxyprogesterone response to a GnRH agonist, buserelin, are characterized by more severe hyperandrogenemia, glucose-stimulated beta-cell insulin secretion, and worse insulin resistance than those without evidence of FOH. Our data may be consistent with the hypothesis that excess insulin may represent a candidate factor responsible for FOH in these women, through the overactivation of the cytochrome P450 17alpha-hydroxylase/17,20-lyase (CYP17) enzyme pathway.

The origins and sequelae of abnormal neuroendocrine function in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common clinical disorder characterized by ovulatory dysfunction and hyperandrogenaemia. A neuroendocrine hallmark of PCOS is persistently rapid LH (GnRH) pulsatility, which favours pituitary synthesis of LH over that of FSH and contributes to the increased LH concentrations and LH : FSH ratios typical of PCOS. Inadequate FSH levels contribute to impaired follicular development, whereas elevated LH levels augment ovarian androgen production. Whereas luteal phase elevations in progesterone normally slow GnRH pulse frequency, women with PCOS do not experience normal progesterone-mediated slowing, due in part to impaired hypothalamic progesterone sensitivity. This reduction in hypothalamic progesterone sensitivity appears to be mediated by elevated androgens because sensitivity can be restored with the androgen receptor blocker flutamide. The ovulatory and hormonal abnormalities associated with PCOS generally present during puberty, typically associated with hyperandrogenaemia. Along with elevated LH concentration and pulsatility, some girls with hyperandrogenaemia have impaired hypothalamic progesterone sensitivity similar to that seen in adult women with PCOS. We propose that peripubertal hyperandrogenaemia may lead to persistently rapid GnRH pulse frequency via impaired hypothalamic feedback inhibition. The subsequent abnormalities in gonadotropin secretion, androgen production and ovulatory function may support progression towards the adult PCOS phenotype.

FEM1A is a candidate gene for polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among women of reproductive age, and is characterized by infertility, hyperandrogenism and insulin resistance in skeletal muscle. There is evidence for a PCOS gene localized to chromosome 19p13.3. The FEMIA gene maps to chromosome 19p13.3 and is highly expressed in skeletal muscle. FEMIA is a homolog of fem-1, a sex-determination gene of Caenorhabditis elegans that controls masculinization. In a pilot study of Caucasian PCOS patients from our local clinic, we found that one of these five patients exhibited a heterozygous germline missense mutation in FEM1A, designated FEM1A*H500Y. This mutation alters an amino acid conserved from human to C. elegans, and was not found in any of 198 control chromosomes. This missense allele was not found in any of a separate group of 30 PCOS patients from a different regional/ethnic background. Immunostaining of mouse ovary demonstrated that the mouse homolog of FEM1A is expressed in androgen-producing secondary interstitial cells, with a marked increase in expression after puberty, consistent with a key feature of PCOS -- ovarian hyperandrogenism. In conclusion, FEM1A should be considered a candidate gene for PCOS, and more extensive analysis of FEM1A, both coding and regulatory sequences, is warranted in patients and families with PCOS.

Graded inhibition of pulsatile luteinizing hormone secretion by a selective gonadotropin-releasing hormone (GnRH)-receptor antagonist in healthy men: evidence that age attenuates hypothalamic GnRH outflow

Healthy older men manifest concomitant hypoandrogenemia and attenuation of LH pulse size. Because exogenous GnRH remains effective, a plausible intuition is that aging reduces hypothalamic GnRH secretion, thus mediating relative hypogonadotropic hypogonadism. To assess the impact of age on central GnRH outflow indirectly, we quantitated graded suppression of pulsatile LH secretion by saline and escalating doses of a potent and selective GnRH-receptor antagonist, ganirelix, in 18 healthy men ages 23-72 yr. The rationale is that ganirelix should reduce the amplitude of LH pulses in proportion to both drug concentration and endogenous GnRH feedforward. To this end, blood was sampled every 10 min for 2 h before and 16 h after sc administration of saline or ganirelix and for 3 additional hours after iv injection of a fixed dose of GnRH (100 ng/kg); concentrations of LH and ganirelix were measured by immunochemiluminometry and RIA, respectively; and pulsatile LH secretion was quantitated by a deconvolution procedure. Log-linear regression analysis was used to estimate the sensitivity of pulsatile LH secretion to inhibition by a unit increase in serum ganirelix concentrations in each subject. Statistical analyses revealed that increasing age markedly attenuated the capability of ganirelix to decrease LH pulse size (viz., r = -0.648; P = 0.004). In contrast, age did not modify the competitive interaction between injected GnRH and ganirelix. These joint outcomes support the clinical hypothesis that age diminishes hypothalamic GnRH outflow without impairing GnRH action in healthy men.

Gender modulates sequential suppression and recovery of pulsatile growth hormone secretion by physiological feedback signals in young adults

The basic mechanisms that drive the renewal of GH pulses in the human are not understood. Recent ensemble models predict that pulse regeneration requires quenching of an ongoing GH pulse by somatostatin outflow and evocation of a new burst by rebound GHRH release. We reasoned that related principles might explain why women consistently maintain higher-amplitude GH secretory bursts than men. Accordingly, the present study tests the hypothesis that gender modulates the successive dynamics of GH feedback and escape in the morning fasting, when GH pulses are larger in women. To this end, we infused single iv pulses of recombinant human (rh) GH (0, 1, and 3 microg/kg) in eight young men and six women on separate randomly ordered mornings fasting and quantitated serial inhibition and recovery of GH secretion by frequent sampling, immunochemiluminometry, a deconvolution procedure, and regularity analysis. Statistical contrasts revealed gender-comparable peak concentrations and kinetics of rhGH. However, women differed from men by way of: (1) 3.5- and 4.0-fold less feedback suppression of GH secretory-burst mass; (2) more irregular patterns of GH release during negative feedback; and (3) 12-and 14-fold greater postnadir rebound-like GH secretion after rhGH pulses. Mechanistic analyses based on a minimal feedback construct predicted that women generate higher endogenous secretagogue stimulation per unit somatostatin outflow than men. In summary, negative feedback induced by near-physiological GH pulses unmasks prominent gender-related contrasts in hypothalamo-pituitary autoregulation in young adults. A frugal but sufficient explanation of the ensemble outcomes is that women sustain greater hypothalamo-pituitary agonist input than men.

PCOS: an ovarian disorder that leads to dysregulation in the hypothalamic–pituitary–adrenal axis?

This review focuses on the role of the ovaries in the pathogenesis of the polycystic ovarian syndrome. In particular, the failure of follicular development, hypothalamo-pituitary dysregulation, alterations in adrenal steroid output and derangement of intermediary metabolism are discussed in the context of the ovaries. It is concluded that the central and adrenal alterations associated with PCOS are unlikely to be primary but rather are secondary to the events within the ovary.