Serum levels of inhibins are differentially altered in patients with polycystic ovary syndrome: effects of being overweight and relevance to hyperandrogenism

Gonadotropin-releasing hormone regulates transcription of the inhibin B co-receptor, TGFBR3L, via early growth response one

Follicle-stimulating hormone (FSH), a product of pituitary gonadotrope cells, regulates gonadal function and fertility. FSH production is stimulated by gonadotropin-releasing hormone (GnRH) and activin-class ligands of the TGFβ family. Inhibin A and B are TGFβ proteins that suppress FSH synthesis by competitively binding activin type II receptors in concert with the co-receptors betaglycan (TGFBR3) and TGFBR3L. Betaglycan mediates the actions of both inhibins and is broadly expressed. In contrast, TGFBR3L is inhibin B-specific and selectively expressed in gonadotropes. This cell-restricted expression is driven, in part, by steroidogenic factor 1 (SF-1, NR5A1), which stimulates Tgfbr3l/TGFBR3L transcription via two conserved promoter elements. Tgfbr3l expression is lost in mice lacking SF-1 in gonadotropes. However, SF-1 alone is unlikely to fully explain gonadotrope-restricted Tgfbr3l/TGFBR3L expression. Here, we report that GnRH induces binding of the transcription factor, early growth response 1 (EGR1), to the murine Tgfbr3l and human TGFBR3L promoters at a conserved cis-element between the two SF-1 binding sites. In homologous LβT2 cells, GnRH stimulation of Tgfbr3l/TGFBR3L promoter-reporters depends on EGR1 binding to this cis-element. In heterologous cells, over-expressed EGR1 independently and synergistically with SF-1 activates Tgfbr3l/TGFBR3L promoter-reporter activities. In vivo, Tgfbr3l mRNA expression is reduced in the pituitaries of: 1) GnRH-deficient mice, 2) wild-type mice treated with a GnRH receptor antagonist, and 3) gonadotrope-specific Egr1 knockout mice. Gonadectomy, which increases GnRH pulse frequency, enhances Tgfbr3l expression in control but not gonadotrope-specific Egr1 knockouts. Collectively, these data indicate that GnRH stimulates Tgfbr3l/TGFBR3L transcription via EGR1, which acts with SF-1 through conserved promoter elements.

Clinical and biochemical discriminants between functional hypothalamic amenorrhoea (FHA) and polycystic ovary syndrome (PCOS)

BACKGROUND

Secondary oligo/amenorrhoea occurs in 3%-5% of women of reproductive age. The two most common causes are polycystic ovary syndrome (PCOS) (2%-13%) and functional hypothalamic amenorrhoea (FHA) (1%-2%). Whilst both conditions have distinct pathophysiology and their diagnosis is supported by guidelines, in practice, differentiating these two common causes of menstrual disturbance is challenging. Moreover, both diagnoses are qualified by the need to first exclude other causes of menstrual disturbance.

AIM

To review clinical, biochemical and radiological parameters that could aid the clinician in distinguishing PCOS and FHA as a cause of menstrual disturbance.

RESULTS

FHA is uncommon in women with BMI > 24 kg/m2 , whereas both PCOS and FHA can occur in women with lower BMIs. AMH levels are markedly elevated in PCOS; however, milder increases may also be observed in FHA. Likewise, polycystic ovarian morphology (PCOM) is more frequently observed in FHA than in healthy women. Features that are differentially altered between PCOS and FHA include LH, androgen, insulin, AMH and SHBG levels, endometrial thickness and cortisol response to CRH. Other promising diagnostic tests with the potential to distinguish these two conditions pending further study include assessment of 5-alpha-reductase activity, leptin, INSL3, kisspeptin and inhibin B levels.

CONCLUSION

Further data directly comparing the discriminatory potential of these markers to differentiate PCOS and FHA in women with secondary amenorrhoea would be of value in defining an objective probability for PCOS or FHA diagnosis.

Is ovarian reserve associated with body mass index and obesity in reproductive aged women? A meta-analysis

OBJECTIVE

The associations of body mass index (BMI) and obesity with ovarian reserve are controversial. This systematic review and meta-analysis was conducted to investigate the associations in reproductive-aged women.

METHODS

PubMed and Scopus were searched up to December, 2016. Original studies on the association of BMI with ovarian reserve markers, anti-Mullerian hormone (AMH), follicle-stimulating hormone (FSH), inhibin β, and antral follicle count (AFC), either according to BMI categories or a continuous variable, were selected. Analyses were stratified into three groups based on polycystic ovary syndrome (PCOS) and fertility status of women.

RESULTS

Of 4,055 records identified, 45 studies were eligible for inclusion. Comparing the obese with nonobese, the pooled mean differences (MDs) and 95% confidence intervals (CIs) were -1.08 (95% CIs -1.52, -0.63) ng/mL for AMH, -0.22 (95% CIs -0.39, -0.06) mIU/mL for FSH, -0.09 (95% CIs -0.60, 0.42) for AFC, and -21.06 (95% CIs -41.18, -0.85) pg/mL for inhibin β in overall populations. The MDs were significant for AMH in fertile non-PCOS and PCOS women, and for FSH only in PCOS women. Fisher's Z showed significant correlations of BMI with AMH in the overall populations (-0.15 [95% CIs -0.20, -0.11]) and in all subgroups, and with FSH in the fertile non-PCOS women (-0.16 [95% CIs -0.28, -0.04]).

CONCLUSION

Ovarian reserve markers of AMH and FSH are significantly lower in obese than in nonobese women, and BMI is negatively correlated with AMH in all study populations, and with FSH in fertile non-PCOS subgroups. PCOS and fertility status do not appear to affect the associations.

Determination of insulin resistance and its relationship with hyperandrogenemia,anti-Müllerian hormone, inhibin A, inhibin B, and insulin-like peptide-3 levels in adolescent girls with polycystic ovary syndrome

Background/aim

This study aims to investigate the association between polycystic ovary syndrome (PCOS) and obesity and insulin resistance (IR) with respect to anti-Müllerian hormone (AMH), inhibin A (INH-A), inhibin B (INH-B), and insulin-like peptide 3 (INSL3) levels, all factors which may have an impact on IR.

Materials and methods

In this cross sectional study, 52 adolescent girls diagnosed with PCOS[groups: nonobese (NO), n = 23; overweight/obese (OW/O), n = 29] were included. Blood samples were obtained to measure AMH, INH-B, INH-A, and INSL3 levels, together with hormonal and biochemical assessments. Oral glucose tolerance test (OGTT) was performed and the indexes of IR [homeostasis model assessment: insulin resistance (HOMA-IR) and Matsuda index] were calculated.

Results

Insulin resistance was 56.5% with OGTT and 30.4% with HOMA-IR in nonobese-PCOS girls. There was a correlation between INH-A and HOMA-IR even when controlled for body mass index (BMI). INH-B and FAI also had correlations with HOMA-IR which disappeared when controlled for BMI. In regression analyses, AMH (odds ratio = [0.903, P = 0.015) and FAI (odds ratio = 1.353, P = 0.023) are found to be contributors to IR. Their effect was BMI-independent. In ROC analysis, the cutoff value for FAI was 5.93 (sensitivity 71%) to define IR in PCOS girls.

Conclusion

AMH and FAI may contribute to IR (defined by OGTT) in PCOS. FAI might be used as a supporting IR marker (defined by OGTT) in adolescent girls with PCOS.

Anti-Müllerian Hormone and Inhibin-A, but not Inhibin-B or Insulin-Like Peptide-3, may be Used as Surrogates in the Diagnosis of Polycystic Ovary Syndrome in Adolescents: Preliminary Results

OBJECTIVE

Polycystic ovary syndrome (PCOS) is a common endocrine problem in adolescents with an increasing prevalence of 30%. Pursuing new biomarkers with high specificity and sensitivity in the diagnosis of PCOS in adolescents is currently an active area of research. We aimed to investigate the diagnostic value of anti-Müllerian hormone (AMH), insulin-like peptide-3 (INSL3), inhibin-A (INH-A), and inhibin-B (INH-B) in adolescents with PCOS and also to determine the association, if any, between these hormones and clinical/laboratory findings related with hyperandrogenism.

METHODS

The study group comprised 53 adolescent girls aged between 14.5 and 20 years who were admitted to our outpatient clinic with symptoms of hirsutism and/or irregular menses and diagnosed as having PCOS in accordance with the Rotterdam criteria. Twenty-six healthy peers, eumenorrheic for at least two years and body mass index-matched, constituted the controls. Fasting blood samples for hormones [luteinizing hormone (LH), follicle-stimulating hormone (FSH), dehydroepiandrosterone-sulfate (DHEAS), androstenedione (D4-A), total/free testosterone (T/fT), sex hormone binding globulin (SHBG), AMH, INSL3, INH-A, INH-B] were drawn after an overnight fast.

RESULTS

In the PCOS group, 83% of the subjects were oligomenorrheic/amenorrheic and 87% had hirsutism. The LH, LH/FSH ratio, total T, fT, free androgen-index (FAI), DHEAS levels were significantly higher (p=0.005, p=0.042, p=0.047, p<0.001, p=0.007, p=0.014, respectively) and SHBG was significantly lower (p=0.004) in PCOS patients as compared to the controls. Although the INSL-3 and INH-B levels showed no difference between the groups (p>0.05), AMH and INH-A levels were found to be significantly higher in the PCOS group compared to the controls (p<0.001, p<0.001, respectively). In multiple linear regression analysis, WC SDS (p=0.028), logD4-A (p=0.033), logSHBG (p=0.031), and total ovarian volume (p=0.045) had significant effects on AMH levels, and LH (p=0.003) on INH-A levels. In receiver-operating characteristic analysis, the cut-off values for AMH and INH-A were 6.1 ng/mL (sensitivity 81.1%) and 12.8 pg/mL (sensitivity 86.8%), respectively, to diagnose PCOS. When AMH and INH-A were used in combination, the sensitivity (96.2%) increased.

CONCLUSION

INSL3 and INH-B were not found to have diagnostic value in adolescents with PCOS. On the other hand, it was shown that INH-A could be used as a new diagnostic biomarker in addition to AMH.

Circulating anti-Müllerian hormone levels in relation to nutritional status and selected adipokines levels in polycystic ovary syndrome

OBJECTIVE

The aim of the study was to analyse the relationship between nutritional status, selected adipokines and plasma anti-Müllerian hormone (AMH) levels in women with polycystic ovary syndrome (PCOS).

STUDY DESIGN PATIENTS AND MEASUREMENTS

A prospective, cross-sectional study, involving 87 PCOS (48 obese) women and 67 non-PCOS women (36 obese). Anthropometric parameters were measured, and body composition was determined by the bioimpedance method. Fasting serum glucose, androgens, FSH, LH, SHBG, insulin, AMH, apelin-36, adiponectin, leptin and omentin-1 were measured.

RESULTS

Plasma AMH levels were significantly higher in PCOS compared to the non-PCOS group (7.8 ± 4.3 ng/ml vs 44 ± 2.4 ng/ml; P < 0.001). Furthermore, AMH levels were higher in both PCOS and non-PCOS normal weight than in obese subgroups (8.9 ± 4.4 ng/ml vs 7.0 ± 4.0 ng/ml; P < 0.05 and 5.1 ± 2.4 ng/ml vs 3.9 ± 2.3 ng/ml; P < 0.05). There were negative correlations between AMH levels and anthropometric parameters (body mass, BMI, fat mass and percentage, as well as waist circumference) and plasma omentin-1 concentrations (R = -0.28, P < 0.001; R = -0.30, P < 0.001; R = -0.36, P < 0.001; R = -0.34, P < 0.001; R = -0.23, P < 0.01; and R = -0.20, P < 0.05, respectively) in all study groups. In multiple regression analysis, circulating AMH level variability was explained by omentin-1 levels and anthropometric parameters (excluding waist circumference).

CONCLUSIONS

In this observational study, nutritional status appears to be the main factor influencing circulating AMH levels independent of PCOS. The observed AMH association with omentin-1 levels suggests that this adipokine may be a link between hormonal dysfunction of adipose tissue related to obesity and decreased AMH secretion.

Inhibin at 90: from discovery to clinical application, a historical review

When it was initially discovered in 1923, inhibin was characterized as a hypophysiotropic hormone that acts on pituitary cells to regulate pituitary hormone secretion. Ninety years later, what we know about inhibin stretches far beyond its well-established capacity to inhibit activin signaling and suppress pituitary FSH production. Inhibin is one of the major reproductive hormones involved in the regulation of folliculogenesis and steroidogenesis. Although the physiological role of inhibin as an activin antagonist in other organ systems is not as well defined as it is in the pituitary-gonadal axis, inhibin also modulates biological processes in other organs through paracrine, autocrine, and/or endocrine mechanisms. Inhibin and components of its signaling pathway are expressed in many organs. Diagnostically, inhibin is used for prenatal screening of Down syndrome as part of the quadruple test and as a biochemical marker in the assessment of ovarian reserve. In this review, we provide a comprehensive summary of our current understanding of the biological role of inhibin, its relationship with activin, its signaling mechanisms, and its potential value as a diagnostic marker for reproductive function and pregnancy-associated conditions.

Decreased inhibin B responses following recombinant human chorionic gonadotropin administration in normal women and women with polycystic ovary syndrome

OBJECTIVE

To determine whether granulosa cells contribute to excess androgen production, by assessing inhibin B (Inh B) responses to hCG in women with polycystic ovary syndrome (PCOS) and in normal women.

DESIGN

Prospective study.

SETTING

Academic medical center.

PATIENT(S)

Twenty women with PCOS and 16 normal women.

INTERVENTION(S)

Blood samples obtained before and 24 hours after injection of 25 μg recombinant hCG (r-hCG).

MAIN OUTCOME MEASURE(S)

Basal and stimulated Inh B, E2, androstenedione (A), and T responses after r-hCG administration.

RESULT(S)

In normal and PCOS women, r-hCG induced a significant reduction of Inh B levels. Lowered Inh B responses were not related to body mass index, PCOS status, or age by multivariate regression. Recombinant hCG significantly increased serum A and E2 in both normal and PCOS women.

CONCLUSION(S)

In normal and PCOS women, Inh B production was decreased following r-hCG administration. These findings strongly suggest that in PCOS women androgen excess is not enhanced by LH-stimulated Inh B production.

CLINICAL TRIAL REGISTRATION NUMBER

NCT00747617.

First intention IVF protocol for polycystic ovaries: does oral contraceptive pill pretreatment influence COH outcome?

BACKGROUND

Morphological aspect of polycystic ovaries (PCO) is a very common finding in an IVF center population: this includes PCOS patients identified in 18-25% of the couples presenting with infertility and so called "sonographic PCO only" the prevalence of which has been estimated as high as 33% in asymptomatic patients. Finding the optimal first intention IVF protocol for polycystic ovaries patients is still challenging in order to improve the controlled ovarian hyperstimulation (COH) outcome while avoiding ovarian hyperstimulation syndrome (OHSS). It has been suggested that women with PCO would benefit from a longer period of pituitary down-regulation. The purpose of this study was to compare an extended duration of OCP pretreatment with a classic GnRH agonist protocol.

METHODS

A single center prospective non-randomized study was performed from January 2009 to December 2010 in the Lille University Hospital including 113 women diagnosed with PCO(S) according to the Rotterdam ultrasonographic criteria and undergoing their first IVF attempt. Comprehensive hormonal and ultra-sonographic assessments were collected during COH in these patients. LH and androgen suppression and dynamics of follicular growth were compared between the two protocols as well as the COH outcome in terms of oocyte/embryo number and quality, implantation and pregnancy rates.

RESULTS

No significant difference was observed between the two groups concerning dynamics of follicular growth and hormonal values. Clinical and ongoing pregnancy rates were significantly lower in the OCP group despite same oocyte and embryo quality. Nevertheless, the cumulative pregnancy rate did not differ between the two groups. The incidence of OHSS was not statistically significant.

CONCLUSIONS

Extended duration of OCP pretreatment, as a first intention IVF protocol for PCO patients, does not improve the pattern of follicular growth nor the oocyte and embryo quality.

Polycystic ovaries at ultrasound: normal variant or silent polycystic ovary syndrome?

OBJECTIVE

It is not known whether polycystic ovaries (PCO) are an ovarian appearance without pathological meaning or whether they share with polycystic ovary syndrome (PCOS) the same ovarian follicle abnormality. There are few studies including strictly selected women with PCO but without other criteria of PCOS. In order to address these issues, we compared hormonal, metabolic and ultrasound parameters obtained from patients with PCO only, patients with PCOS and controls.

METHODS

This was a comparative analysis including three age-matched groups of 95 patients, who were included consecutively in a database: controls, patients with sonographic PCO but no symptoms (PCO group) and patients with PCOS. A clinical examination, fasting serum sampling and pelvic ultrasound examination were performed between cycle days 2 and 5 and results were compared between groups.

RESULTS

The median serum anti-Mullerian hormone (AMH) level in the PCO group was intermediate between that in controls and that in the PCOS group (33.6 pmol/L, 19.8 pmol/L and 63.3 pmol/L, respectively), the differences being significant after adjustment for follicle number (P < 0.05), while the mean androgen serum level in the PCO group was similar to that in the control group and significantly lower than that in the PCOS group (P < 0.05) (median serum testosterone levels: 0.90 nmol/L, 0.79 nmol/L and 1.39 nmol/L; median androstenedione levels: 5.25 nmol/L, 4.37 nmol/L and 6.09 nmol/L, respectively). Body mass index, waist circumference and insulin levels had no effect on these differences.

CONCLUSION

PCO is an abnormal condition, affected women showing no evidence of hyperandrogenism but having higher AMH serum levels compared with controls, suggesting a granulosa cell abnormality in PCO similar to that observed in PCOS. The absence of hyperandrogenism in PCO does not seem linked to the metabolic status.

Inhibin secretion in women with the polycystic ovary syndrome before and after treatment with progesterone

OBJECTIVES

It has been suggested that inhibin secretion is altered in women with the polycystic ovary syndrome (PCOS). However, the contribution of a preceding luteal phase has not been taken into account. The aim of the present study was to investigate whether progesterone in the context of a simulated luteal phase affects basal and FSH-induced inhibin secretion in women with PCOS and elevated LH.

METHODS

Ten women with PCOS and 8 normally cycling women participated in an experimental procedure (Exp) involving the administration of a single injection of recombinant FSH (450 IU sc). In the women with PCOS, the procedure was performed before (Exp 1) and after a 20-day treatment with progesterone (Exp 2), while in the normal women on day 2 of the cycle (Exp 3). Inhibin A and B levels were measured in blood samples taken before and 24 hours after the FSH injection.

RESULTS

Basal LH levels were significantly higher and inhibin A levels were significantly lower in the PCOS group compared to the control group, while inhibin B levels were comparable in the two groups. In the PCOS group, after treatment with progesterone inhibin A and LH but not inhibin B levels decreased significantly (p < 0.05). After the FSH injection, inhibin A and B levels increased significantly in the women with PCOS (Exp 1 and Exp 2) but not in the control women (Exp 3).

CONCLUSIONS

In women with PCOS, as compared to control women, the dissimilar pattern of inhibin A and inhibin B secretion in response to FSH appears to be independent of a preceding simulated luteal phase. It is possible that compared to normal ovaries, the PCOS ovaries are less sensitive to endogenous LH regarding inhibin A secretion and more sensitive to exogenous FSH stimulation in terms of inhibin A and inhibin B secretion.

Relating smoking, obesity, insulin resistance, and ovarian biomarker changes to the final menstrual period

To determine if smoking, obesity, and insulin resistance mediated age at final menstrual period (FMP), we examined anti-Müllerian hormone (AMH), inhibin B, and follicle-stimulating hormone (FSH) as biomarkers of changing follicle status and ovarian aging. We performed a longitudinal data analysis from a cohort of premenopausal women followed to their FMP. Our results found that smokers had an earlier age at FMP (P < 0.003) and a more rapid decline in their AMH slope relative to age at FMP (P < 0.002). Smokers had a lower baseline inhibin B level relative to age at the FMP than nonsmokers (P = 0.002). Increasing insulin resistance was associated with a shorter time to FMP (P < 0.003) and associations of obesity and time to FMP were observed (P = 0.004, in model with FSH). Change in ovarian biomarkers did not mediate the time to FMP. We found that smoking was associated with age at FMP and modified associations of AMH and inhibin B with age at FMP. Insulin resistance was associated with shorter time to FMP independent of the biomarkers. Interventions targeting smoking and insulin resistance could curtail the undue advancement of reproductive aging.

Serum inhibin A concentration in women with polycystic ovarian syndrome and the correlation to ethnicity, androgens and insulin resistance

A prospective case-series in an academic hospital clinic was performed to determine whether there is a relationship between polycystic ovarian syndrome (PCOS) and ethnicity. Also, serum inhibin A concentrations were compared between PCOS and normal-ovulatory women. The possibility of a correlation between inhibin A, androgens and insulin resistance in PCOS women was evaluated. Serum inhibin A concentrations were measured in anovulatory PCOS patients (n=32) and in control women of reproductive age (n=16). Statistical analysis was performed using the Mann-Whitney U-test. Serum concentrations of inhibin A, follicle-stimulating hormone, LH, prolactin, thyroid-stimulating hormone, fasting glucose, insulin, testosterone, 17-hydroxyprogesterone (17-OHP) and dehydroepiandrosterone sulphate (DHEAS) were measured. Inhibin A concentrations were significantly lower (4.5+/-4.8 pg/ml) when compared with the control group (13.2+/-14.4 pg/ml; P=0.003) and were not significantly different between Hispanic and Caucasian women diagnosed with PCOS. There was no correlation between inhibin A concentrations and insulin, testosterone, free testosterone, 17-OHP, or DHEAS concentrations. In PCOS women, inhibin A concentrations are similar between Hispanic and Caucasian women; however, women with PCOS, regardless of ethnicity, have a lower inhibin A concentration compared with normal-ovulatory women. No correlation was observed between inhibin A androgens and insulin resistance in women diagnosed with PCOS.

[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.

Inhibins as diagnostic markers in human reproduction

Over the past 75 years, many publications have focused on measurement of inhibin concentration and/or activity in biological samples in order to understand its role in physiology and disease. This chapter highlights the accomplishments within this area of research over the past decade including development of specific inhibin assays. Inhibin A is a marker of dominant follicle and corpus luteum activity and decreases in polycystic ovary syndrome (PCOS). Inhibin A increases in gestational diseases such as pre-eclampsia and fetal Down's syndrome, and this increase in inhibin A improves early diagnosis of both conditions. The measurement of inhibin A in women with threatened abortion provides useful information about the likelihood of pregnancy loss. Inhibin B increases markedly in women with granulosa cell tumor and appears closely related to gametogenesis in men, that is, reflecting Sertoli cell activity. On the contrary, Inhibin B decreases in women with declining ovarian function and correlates with female response to ovulation induction. This review evaluates the biochemical significance ofinhibins including their use in clinical practice.

Diminished paternity and gonadal function with increasing obesity in men

OBJECTIVE

To examine the relationship of male obesity and reproductive function.

DESIGN

Observational study.

SETTING

Academic medical center.

PATIENT(S)

Eighty-seven adult men, body mass index (BMI) range from 16.1 to 47.0 kg/m(2) (mean = 29.3 kg/m(2); SD = 6.5 kg/m(2)).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Reproductive history, physical examination, inhibin B, FSH, LH, T, and unbound T levels, and semen analysis.

RESULT(S)

Body mass index was negatively correlated with testosterone (r = -0.38), FSH (r = -0.22), and inhibin B levels (r = -0.21) and was positively correlated with E(2) levels (r = 0.34). Testosterone also negatively correlated with skinfold thickness (r = -0.30). There was no correlation of BMI or skinfold thickness with semen analysis parameters (sperm density, volume, motility, or morphology). Inhibin B level correlated significantly with sperm motility (r = 0.23). Men with paternity had lower BMIs (28.0 kg/m(2) vs. 31.6 kg/m(2)) and lower skinfold thickness (24.7 mm vs. 34.1 mm) than men without.

CONCLUSION(S)

Obesity is an infertility factor in otherwise normal men. Obese men demonstrate a relative hypogonadotropic hypogonadism. Reduced inhibin B levels and diminished paternity suggest compromised reproductive capacity in this population.

Polycystic ovarian syndrome: pathophysiology, molecular aspects and clinical implications

Polycystic ovarian syndrome (PCOS) is universally recognised as the commonest endocrinopathy of women. The definition and the aetiological hypotheses of PCOS are continuously evolving to accommodate expanding knowledge on the syndrome, which is now known to be more complex than purely a reproductive disorder. Increased androgen synthesis, disrupted folliculogenesis and insulin resistance lie at the pathophysiological core of PCOS. An intriguing concept involves the perpetuation of a vicious circle with endocrine/reproductive and metabolic components. An unfavourable metabolic environment may unmask genetic traits of ovarian dysfunction, and the unfolding endocrine derangement could further aggravate the metabolic disarray. This article reviews the molecular mechanisms known to underlie the ovarian and metabolic abnormalities characterising PCOS. The putative interdependence between reproductive and metabolic aspects of PCOS, and therapeutic implications for the management of PCOS, are also discussed.

Changes in serum anti-mullerian hormone level during low-dose recombinant follicular-stimulating hormone therapy for anovulation in polycystic ovary syndrome

CONTEXT

We previously hypothesized that the excess of anti-müllerian hormone (AMH) at the level of selectable follicles could be involved in the follicular arrest of polycystic ovary syndrome (PCOS), mainly through inhibition of FSH effect on aromatase expression.

OBJECTIVE

In this study, we investigated whether a decrease in the serum AMH level was concomitant to the appearance of a dominant follicle induced by administration of mild amounts of exogenous FSH in women with PCOS.

DESIGN

A total of 30 women with PCOS in whom anovulation was resistant to clomiphene citrate received recombinant FSH using the low-dose step-up protocol during only one cycle. Serum levels of estradiol, AMH, LH, FSH, inhibin B, and ultrasound parameters were assessed twice a week until 3 d after the appearance of one or more dominant follicle(s).

RESULTS

The day of dominance (d 0) was defined by the appearance of at least one follicle more than 10 mm growing 2 mm/d. From d -14 before dominance to d +3, the mean serum AMH level and the 2- to 5-mm follicle number at ultrasound declined steadily, although not significantly by ANOVA. Mean AMH relative values (100% being the value at d 0) declined significantly (P = 0.04), from 125 +/- 32% at d -14 to 105 +/- 15% at d -4. Within the same time lag, the mean FSH relative values increased from 91 +/- 17% to 107 +/- 19% (P = 0.013). In the 87 samples obtained from d -14 to -4, absolute values of AMH were positively and negatively associated with those of LH and FSH, respectively, in an independent manner (P = 0.009 and P = 0.03, respectively). In the 55 samples collected at d 0 and +3, they were negatively correlated to those of estradiol (r = -0.272; P < 0.05).

CONCLUSIONS

These data suggest that in anovulatory women with PCOS, gently increasing the serum FSH level reduces the AMH excess, thus relieving the inhibition from the latter on aromatase expression by selectable follicles and allowing the emergence of a dominant follicle.

Acute effects of metformin therapy include improvement of insulin resistance and ovarian morphology

OBJECTIVE

To evaluate the acute effects of metformin therapy on biochemical markers and polycystic ovarian morphology among insulin-resistant (IR) and noninsulin-resistant (NIR) patients with polycystic ovary syndrome (PCOS).

DESIGN

Prospective interventional study.

SETTING

Reproductive endocrinology clinic in a university hospital.

PATIENT(S)

Five IR and five NIR patients with PCOS. The mean age of patients was 29.5 +/- 4.8 years (range, 23-36 years).

INTERVENTION

Metformin therapy, using 850 mg orally per day for 1 week.

MAIN OUTCOME MEASURE(S)

Serum levels of T, FSH, and LH, fasting glucose/insulin ratio, levels of anti-Müllerian hormone (AMH) and inhibin B, and antral follicle count.

RESULT(S)

Levels of AMH and inhibin B were statistically significantly higher in patients with PCOS compared to controls (2.81 +/- 1.79 ng/mL versus 0.95 +/- 1.17 ng/mL, and 56.24 +/- 29.39 pg/mL versus 17.89 +/- 12.87 pg/mL, respectively). Levels of AMH and inhibin B were similar among IR and NIR patients with PCOS (2.77 +/- 1.92 ng/mL versus 2.85 +/- 1.89 ng/mL, and 53.96 +/- 28.58 pg/mL versus 58.51 +/- 33.28 pg/mL, respectively). One week of metformin therapy did not alter either AMH or inhibin B levels. However, there was a statistically significant increase in glucose/insulin ratios (4.59 +/- 1.57 versus 6.35 +/- 3.6), and a significant decrease in the number of antral follicles after 1 week of metformin therapy (38.8 +/- 19.3 versus 23.1 +/- 7.4).

CONCLUSION(S)

Levels of AMH and inhibin B are significantly increased in patients with PCOS compared to controls, but are not associated with insulin resistance. Low-dose metformin therapy improves IR and polycystic ovary morphology, even though levels of T, AMH, and inhibin B remain unchanged.

Association of anti-mullerian hormone levels with obesity in late reproductive-age women

OBJECTIVE

To describe anti-mullerian hormone (AMH) levels in healthy late reproductive age women and test the hypothesis that AMH levels are lower in obese compared to non-obese women.

DESIGN

Cross-sectional study of AMH levels. Longitudinal analysis of a subgroup with 10 AMH measures over 8 years to support the cross-sectional results.

SETTING

A population-based cohort of healthy late reproductive-age women.

PARTICIPANTS

Selected from the cohort to provide comparisons of body mass index (BMI), menopausal status, age and race (n = 122).

INTERVENTIONS

AMH levels were determined from blood samples collected in the parent study.

MAIN OUTCOME MEASURE

Serum levels of AMH.

RESULTS

AMH levels were 65% lower in obese women compared to non-obese women (0.016 ng/mL and 0.046 ng/mL, respectively). The geometric mean ratio was 0.35; 95% CI 0.13, 0.92, P=.034. AMH levels were significantly lower in the menopausal transition compared to premenopausal women and were significantly lower in all age groups > or =40 years compared to the 35-39 year-old women. BMI remained significantly associated with AMH levels in multivariable models that included adjustments for menopausal status, age, race and cycle day. In the longitudinal analysis of a subgroup, obese women had significantly lower mean AMH levels over the 8-year interval compared to the non-obese women (0.459 ng/mL; CI 0.28, 0.75 and 0.566 ng/mL; CI 0.34, 0.94, respectively; P=.016), corroborating the cross-sectional study results.

CONCLUSIONS

Obese women have lower AMH levels compared to non-obese women in the late reproductive years. The findings offer further evidence of the complex relationships between obesity and reproductive hormone levels in women.

Effect of laparoscopic ovarian diathermy on circulating inhibin B in women with anovulatory polycystic ovary syndrome

BACKGROUND

Laparoscopic ovarian diathermy (LOD) frequently induces ovulation in patients with polycystic ovary syndrome (PCOS). The mechanism by which this effect occurs remains largely unexplained. The aim of this study was to measure changes in inhibin B production in response to LOD to see whether this could explain the mechanism of action of LOD.

METHODS

This prospective study included 50 anovulatory women with PCOS. All women underwent LOD. Blood samples were collected before and after LOD to measure plasma concentrations of inhibin B, gonadotrophins and androgens.

RESULTS

The pre-operative median plasma concentration of inhibin B was 110.0 pg/ml (range 19.0-567.0 pg/ml). There was a statistically significant inverse correlation (r= -0.286; P < 0.05) between body mass index (BMI) and inhibin B. Non-obese women with PCOS (BMI <or= 30 kg/m2; n=37) displayed significantly (P < 0.05) higher plasma inhibin B concentrations [122.0 pg/ml (range 19.0-567.0 pg/ml)] compared with those [51.0 pg/ml (range 27.0-201.0 pg/ml)] of obese PCOS women (BMI > 30 kg/m2; n=13). Following LOD, 39 women ovulated. No statistically significant change of inhibin B after LOD was observed in the overall group of women with PCOS or in the subgroup of non-obese PCOS women with higher pre-operative inhibin B.

CONCLUSIONS

The lack of any change of inhibin B after LOD makes it unlikely that this hormone has any role to play in the mechanism of action of LOD.

Luteal-phase inhibin A and follicular-phase inhibin B levels are not characteristic of patients with an elevated LH-to-FSH ratio

PURPOSE

To test whether serum inhibin levels are related to differences in gonadotropin concentrations between patients with an elevated LH-to-FSH ratio (ELF patients) and controls.

METHODS

32 ELF patients were matched with controls by age, body mass index (BMI), and cycle length.

RESULTS

No statistically significant difference was found in follicular-phase inhibin B levels or midluteal inhibin A levels between cases and controls. Significant negative correlation was observed between follicular-phase inhibin B concentrations and BMI in ELF patients but not among controls. LH and FSH were positively related to inhibin B levels in ELF patients. Midluteal inhibin A correlated with sex hormone-binding globulin in controls but not in ELF patients.

CONCLUSIONS

Neither follicular-phase inhibin B levels nor midluteal inhibin A levels are characteristic of patients with an elevated LH-to-FSH ratio. Opposite correlations with LH and BMI suggest dysregulation of inhibin secretion rather than dimeric inhibins having a central role to the endocrinological imbalance observed in polycystic ovary syndrome.

Ovarian feedback, mechanism of action and possible clinical implications

The secretion of gonadotrophins from the pituitary in women is under ovarian control via negative and positive feedback mechanisms. Steroidal and non-steroidal substances mediate the ovarian effects on the hypothalamic-pituitary system. During the follicular phase of the cycle, estradiol (E(2)) plays a key role, while circulating progesterone (at low concentrations) and inhibin B contribute to the control of LH and FSH secretion respectively. During the luteal phase, both E(2) and progesterone regulate secretion of the two gonadotrophins, while inhibin A plays a role in FSH secretion. The intercycle rise of FSH is related to changes in the levels of the steroidal and non-steroidal substances during the luteal-follicular transition. In terms of the positive feedback mechanism, E(2) is the main component sensitizing the pituitary to GnRH. Activity of a non-steroidal ovarian substance, named gonadotrophin surge-attenuating factor (GnSAF), has been detected after ovarian stimulation. It is hypothesized that GnSAF, by antagonizing the sensitizing effect of E(2) on the pituitary, regulates the amplitude of the endogenous LH surge at midcycle. Disturbances in the feedback mechanisms can occur in various abnormal conditions or after treatment with pharmaceutical compounds that interfere with the production or the action of endogenous hormones.

Müllerian-inhibiting substance reflects ovarian findings in women with polycystic ovary syndrome better than does inhibin B

OBJECTIVE

To investigate Müllerian-inhibiting substance (MIS) levels in women with polycystic ovary syndrome (PCOS), as well as relationships to ovarian morphology, levels of inhibin B, and other reproductive hormones.

DESIGN

Prospective clinical study.

SETTING

Academic endocrinology centers in Palermo, Italy and New York.

PATIENT(S)

Forty-six women with PCOS, recruited on the basis of the classic criteria of chronic anovulation and hyperandrogenism, and 25 age-matched ovulatory controls.

INTERVENTION(S)

Fasting blood was obtained in all subjects in the early follicular phase (days 5-6) after spontaneous or induced menses (in PCOS), and transvaginal ultrasounds were performed.

MAIN OUTCOME MEASURE(S)

Assessment of values for luteinizing hormone (LH), testosterone (T), androstenedione (A), estradiol (E2), inhibin B, MIS, fasting insulin, and the calculated quantitative sensitivity check index (QUICKI), as well as assessments of ovarian volume and blood flow.

RESULT(S)

Women with PCOS had higher LH, T, and A; higher insulin and lower QUICKI; and higher ovarian volume and lower pulsatility index. Inhibin B concentrations were statistically significantly higher in PCOS patients (70 +/- 8.0 vs. 40 +/- 3.4 pg/mL), as was MIS (6.7 +/- 0.9 vs. 4.6 +/- 0.5 ng/mL). Inhibin B had a statistically significant direct correlation with levels of MIS (r = 0.351). However, MIS, but not inhibin B, had a statistically significant positive correlation with ovarian size (r = 0.350); the reproductive hormones LH, T, A, and E2; and insulin (r = 0.249), independent of body mass index. Women with PCOS with the highest levels of MIS had higher ovarian volumes and values of LH, T, A, and insulin.

CONCLUSION(S)

Measurements of MIS reflect ovarian findings in PCOS better than levels of inhibin B and are more frequently elevated. However, MIS lacks sensitivity for use as a diagnostic tool in PCOS.

The relationship between obesity and race on inhibin B during the menopause transition

OBJECTIVE

Data are lacking on the effects of obesity and race on inhibin B levels during the menopause transition. The purpose of this study was to determine the relationship among inhibin B levels, body mass index (BMI), and race during the menopause transition.

DESIGN

In the Penn Ovarian Aging Study, a prospective cohort study of reproductive aging, 436 women aged 35 to 47 years were followed up with serial hormones, anthropometric measures, and questionnaires for 6 years. Univariate and multivariable analyses were performed comparing mean log transformed inhibin B levels among menopause stages, age groups, BMI categories, races, and smoking groups.

RESULTS

In the univariate analyses, mean inhibin B levels were negatively associated with menopause stage, age, and BMI, but not significantly with race or smoking. Interactions of menopause status and BMI were significant (P < 0.001). Premenopausal women with a BMI of 25 or higher had significantly lower inhibin B levels compared with women with a BMI of less than 25 (41.8 pg/mL vs 58.4 pg/mL, P < 0.001), whereas postmenopausal women with a BMI of 30 or higher had significantly higher inhibin B levels compared with the postmenopausal women with a BMI of less than 25 (29.1 pg/mL vs 26.7 pg/mL, P < 0.001).

CONCLUSIONS

Although BMI is a significant independent predictor of inhibin B levels, the relationship between BMI and inhibin B changes with advancing menopause stage. These data provide additional evidence that obesity influences hormones during the menopause transition.

Ovarian size and blood flow in women with polycystic ovary syndrome and their correlations with endocrine parameters

OBJECTIVE

To determine how common polycystic ovarian morphology may be in women given the clinical diagnosis of polycystic ovary syndrome (PCOS) based on chronic anovulation and hyperandrogenism and whether certain hormonal factors correlate with ovarian morphology and blood flow.

DESIGN

Prospective study.

SETTING

Two academic endocrinology centers in Italy.

PATIENT(S)

Three hundred twenty-six women with PCOS and 50 age-matched and weight-matched ovulatory women.

INTERVENTION(S)

Ultrasound assessment of ovarian morphology in patients and controls and ovarian blood flow and fasting hormone levels in a subset of 50 patients and matched controls.

MAIN OUTCOME MEASURE(S)

Ovarian morphological assessments, ovarian blood flow by pulsatility index (PI) and resistance index (RI), and measurements of gonadotropins, estrogen, sex hormone-binding globulin, androgens, inhibin B, glucose, and insulin.

RESULT(S)

Using strict ultrasound criteria, 195 woman (60%) had enlarged ovaries, 135 (35%) had normal ovarian size but characteristic morphology, and 16 (5%) had normal size and morphology. Ovarian blood flow was increased (reduced PI and RI) in PCOS. All hormonal parameters were elevated in PCOS. Ovarian size correlated only with insulin and a measure of insulin resistance. Ovarian blood flow correlated positively with insulin, T, free T, and E2 but not with luteinizing hormone. Inhibin B showed a negative correlation with ovarian blood flow.

CONCLUSION(S)

When a clinical diagnosis of PCOS was made, virtually all women were found to have characteristic ovarian morphology. Insulin correlated with increased ovarian size as well as with increased blood flow. Blood flow also correlated positively with sex steroids but negatively with inhibin B.

Abnormal inhibin A and inhibin B secretion in obese women with and without insulin resistance

AIM

The present study aimed to establish inhibin A and B serum levels during the menstrual cycle of obese women, and its usefulness as an index of luteal-phase follicular development.

MATERIALS AND METHODS

Twenty-one obese patients (mean body mass index: 34.9+/-3.7 kg/m2; range: 30.0-45.0 kg/m2) were submitted to basal hormonal measurements and an oral glucose tolerance test after challenge with 75 g glucose. Progesterone and inhibin A and B levels were determined 5-7 days after the menstrual cycle and 7 days prior to expected menses.

RESULTS

As expected, an increase in inhibin A and a decrease in inhibin B were observed when first-phase samples were compared with samples obtained after 15-20 days. On the other hand, the percentage variation of both inhibin A and B was at least four times smaller than the values for normal women described previously by other authors employing the same enzyme-linked immunosorbent assays. A small number of obese women presented ovulatory cycles characterized by progesterone concentration higher than 5.8 ng/ml. The percentage elevation (>190%) of inhibin A in the second samples was in agreement with the progesterone levels, but it seemed to be more sensitive for the detection of follicle luteinization.

CONCLUSION

We conclude that obese women present less percentage variation of both inhibin A and B during the menstrual cycle, associated with a low frequency of ovulatory cycles. In obese women, the percentage increase of inhibin A can represent an additional marker to recognize follicle luteinization.

Do basal inhibin A and inhibin B levels have value in the diagnosis of polycystic ovary syndrome?

In the present study we aimed to investigate whether basal inhibin A and B levels in women with polycystic ovary syndrome (PCOS) would be used in diagnosis of the condition. Forty women with PCOS and 40 women with normal cycles (control group) were evaluated. There was no statistically significant difference in mean age and mean body mass index between the two groups (p > 0.05). Serum levels of inhibin A and B, follicle-stimulating hormone (FSH), luteinizing hormone and total testosterone, and total ovarian volume, were determined in the PCOS group and the control group on day 3. In the PCOS group, total follicle number was obtained by counting follicles of diameter > or =2 mm in both ovaries. Results were evaluated using Student's t test, Pearson correlation and regression tests. There was no significant difference in mean basal inhibin A or inhibin B levels between the two groups. Basal inhibin B levels showed a statistically significant negative correlation with basal FSH levels and a positive correlation with total follicle number in the PCOS group (p < 0.05 and p < 0.01, respectively). We conclude that basal inhibin A or B levels cannot be used in the diagnosis of PCOS.

Cellular expression of protamine 1 and 2 transcripts in testicular spermatids from azoospermic men submitted to TESE-ICSI

Testicular sperm extraction (TESE) combined with ICSI is used to treat azoospermia. However, the factors that influence the outcome of ICSI in this situation are ill-defined. We sought to investigate the expression of protamine 1 (PRM1) and protamine 2 (PRM2) transcripts in testicular spermatids from obstructive and non-obstructive azoospermic men with impaired spermatogenesis. The relationship between PRM1 and PRM2 transcript levels and the TESE-ICSI outcome was evaluated. The cellular expression of PRM1 and PRM2 mRNAs in single testicular spermatids from 41 azoospermic patients (in whom testicular spermatozoa were subsequently recovered and submitted for TESE-ICSI) was determined by radioactive in situ hybridization. Group I contained seven men with congenital, obstructive azoospermia and whose testicular biopsies indicated quantitatively normal spermatogenesis. Group II consisted of 18 azoospermic men with moderately impaired spermatogenesis. Sixteen men with non-obstructive azoospermia and severely deranged spermatogenesis (i.e. mixed atrophy with small foci of spermatids and spermatozoa) constituted group III. The spermatids of men with severely deranged spermatogenesis exhibited significant lower PRM1 mRNA expression than in the other patient groups. There were no significant inter-group differences in PRM2 mRNA expression. Spermatid PRM1 expression was lower in non-pregnant couples than in pregnant couples. The low number of spermatids in cases of mixed atrophy with small spermatogenic foci is associated with significantly lower PRM1 expression and a lower pregnancy rate. These results emphasize the role of PRM1 as a potentially critical factor in post-ICSI embryonic development.

Inhibins in female and male reproductive physiology: role in gametogenesis, conception, implantation and early pregnancy

A great deal of new information has arisen in the recent years concerning inhibin physiology and clinical relevance in reproductive medicine. It is now recognized that the two inhibin isoforms, named inhibin A and inhibin B, are produced by the gonads in the course of gamete maturation and in women have a different pattern of secretion throughout the menstrual cycle. Since inhibins are also produced by placenta and fetal membranes, it has been suggested that there is an involvement in physiological adaptation of pregnancy. Evidence from several sources has underlined the clinical usefulness of the measurement of inhibin-related proteins in the diagnosis and follow-up of different fertility disturbances and early pregnancy viability. In the male, inhibin B is produced in the testis, principally by the Sertoli cells. Inhibin B expression and secretion are positively correlated with Sertoli cell function, sperm number, and spermatogenic status and are negatively correlated with FSH. This review covers the most recent advances on the role of inhibins in human reproductive function. Considerable progress in the understanding of inhibin physiology has resulted from selective measurement of the two inhibin molecular forms, named inhibin A and B. Newly recognized alterations of inhibin levels in gynaecological diseases as well as in normal and pathological pregnancy are discussed, with particular emphasis on the potential clinical usefulness of assessing inhibin levels in serum and other biological fluids.

The ovarian markers of the FSH insufficiency in functional hypothalamic amenorrhoea

BACKGROUND

The purpose of this work was to revisit the gonadotrophin insufficiency of functional hypothalamic amenorrhoea (FHA) with the use of relevant ovarian markers.

METHODS

Serum anti-Mullerian hormone (AMH), estradiol (E2), inhibin B, LH and FSH were immunoassayed in 31 women with FHA and in 30 healthy women in early follicular phase. The ovarian antral follicle number (FN) was determined within two distinct diameter ranges (2-5 and 6-9 mm) by ultrasound in real time, the same day as the blood sampling.

RESULTS

The 2-5 mm FN was similar between the two groups, while the 6-9 mm FN was significantly less in FHA than in controls, in relation with lower serum FSH levels (r=0.428; P<0.024). Nine (29%) FHA patients had a low serum basal FSH level (i.e. <4.5 IU/l, 5th percentile of control values). In the 22 (71%) patients with apparently normal FSH, the mean 6-9 mm FN was similar to controls. However, in this sub-group, the mean AMH serum level and the AMH:2-5 mm FN ratio were significantly higher and the mean inhibin B serum level was significantly lower than in controls. No significant relationship was found between the serum LH levels and the FN, AMH or inhibin B values.

CONCLUSION

Only a minority of patients with FHA have a low serum basal FSH level, and we show that this is associated with fewer 6-9 mm follicles at the ovarian level. Despite a normal serum FSH level and 6-9 mm FN in the majority of patients with FHA, the functional follicle markers are abnormal. This suggests that the FSH action on the ovary is incomplete and is not properly reflected by its serum level nor by FN at ultrasound.

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.

Inhibins and adult ovarian function

Inhibin B is predominantly produced by early healthy antral follicles during the luteo-follicular transition of the menstrual cycle. High inhibin B concentrations during the early follicular phase are responsible for the decline in FSH serum levels closing the FSH window and assuring single dominant follicle selection in the human. Early follicular phase inhibin B levels decrease over time, reflecting the recruitment of a diminished cohort of follicles with ovarian ageing. Hence, inhibin B is a predictor of poor response in IVF. In patients with PCOS inhibin B levels (potentially representing the number of healthy, early antral follicles) may be associated with the severity of ovarian dysfunction and consequently may predict ovulation induction outcome. However, inhibin B levels are normal in most PCOS patients suggesting a normal number of healthy follicles despite an increase in overall follicle number. Recent findings indicate that initial inhibin B concentrations can not predict the outcome of ovulation induction by either clomiphene citrate or FSH. Finally, inhibin B levels decrease over time in PCOS.

Elevated serum level of anti-mullerian hormone in patients with polycystic ovary syndrome: relationship to the ovarian follicle excess and to the follicular arrest

The serum level of anti-Mullerian hormone (AMH), a product from granulosa cells involved in follicle growth, has been shown to correlate tightly with the small antral follicle number (FN) at ultrasonography (U/S) in women who do not have polycystic ovary syndrome (PCOS). Because PCOS is associated with a 2- to 3-fold increase in growing FN, we investigated whether an increased AMH serum level correlates to other hormonal and/or U/S features of PCOS. Serum AMH has been assayed in 104 women (59 symptomatic PCOS, 45 controls) between d 2 and 7 after the last either spontaneous or progestin-induced (in PCOS) menstrual period. Mean serum AMH level was markedly increased in the PCOS group (47.1 +/- 22.9 vs. 20.8 +/- 11.6 pmol/liter in controls; P < 0.0001), an increase in the same order of magnitude as the one of the FN in the 2- to 5-mm range at U/S (12.8 +/- 8.3 vs. 4.8 +/- 1.9; P < 0.0001, respectively). The ratio AMH/FN was similar between the two groups (4.8 +/- 3.4 vs. 4.8 +/- 2.9; P = 0.55). By simple regression, both in PCOS and controls, the AMH level was positively related to the 2- to 5-mm FN at U/S (P < 0.0001 and P < 0.03, respectively), but not to the 6- to 9-mm FN, and was negatively correlated to the serum FSH level (P < 0.02 and P < 0.04, respectively). AMH was also positively related to the serum testosterone and androstenedione levels, in PCOS exclusively (P < 0.0005 and <0.002, respectively). No relationship was found between AMH and age, serum estradiol, inhibin B, and LH levels in both groups. After multiple regression only the 2- to 5-mm FN remained significantly related to AMH in PCOS whereas testosterone, androstenedione, and FSH were no longer. In conclusion, the assay of the serum AMH may represent an important breakthrough in the diagnosis and in the understanding of PCOS. Our data suggest that the increase of AMH serum level in PCOS is the consequence of the androgen-induced excess in small antral FN and that each follicle produces a normal amount of AMH. We hypothesize that an increased AMH tone within the cohort could be involved in the follicular arrest of PCOS, by interacting negatively with FSH at the time of selection.

Inhibin B levels on cycle day 3 to predict the ovulatory response in women with PCOS undergoing ovulation induction via low dose step-up gonadotropin protocol

BACKGROUND

In this prospective clinical single blind study, we aimed to investigate whether day 3 serum inhibin B levels in women with polycystic ovarian syndrome(PCOS) are of predictive value for the estimation of the ovarian response to gonadotropins.

METHODS

Ovulation induction with low dose step-up gonadotropin protocol, starting with 75 IU/day, was performed for 30 cycles on 25 patients with PCOS. Day 3 serum inhibin B, follicle-stimulating hormone(FSH) and estradiol, and midluteal serum progesterone levels were measured during each cycle. The correlations between day 3 inhibin B levels and day 3 FSH, day 3 estradiol and midluteal progesterone measurements, as well as the amount of gonadotropin required to provide an ovulatory cycle were investigated.

RESULTS

Five (27.8%) out of 18 cycles with day 3 inhibin levels <50.0 pg/ml; and 11 (91.7%) out of 12 cycles with levels > or = 50.0 pg/ml were ovulatory (chi(2)=9.38, p<0.01). Moreover, day 3 inhibin B levels had statistically significant negative correlation with the gonadotropin used; and significant positive correlation with the midluteal progesterone levels (p<0.05). There wasn't any significant relation between day 3 FSH and estradiol levels with the gonadotropin used and progesterone levels.

CONCLUSIONS

It has been observed that as day 3 serum inhibin B levels increased in women with PCOS, the ovulatory response to gonadotropins and the rate of ovulatory cycles increased significantly.

IVF outcome in anovulatory infertility (WHO group 2)--including polycystic ovary syndrome--following previous unsuccessful ovulation induction

This follow-up study represents IVF treatment characteristics and outcomes in women with World Health Organization (WHO) group 2 anovulatory infertility after previous unsuccessful ovulation induction compared with controls. Furthermore, the possibility of initial screening parameters of these anovulatory women to predict IVF outcome was examined. Twenty-six patients with WHO 2 anovulatory infertility who failed to achieve a live birth following previous induction of ovulation (using clomiphene citrate as first line and exogenous FSH as second line) were compared with 26 IVF patients with tubal infertility matched for age, treatment period and treatment regimen. The WHO 2 patients underwent 49 IVF cycles, whereas the normo-ovulatory controls underwent 46 cycles. In WHO 2 patients 15 cycles were cancelled compared with six cycles in controls (P = 0.04). Cycles were predominantly cancelled due to insufficient response (P = 0.04). In cases in whom the cycle was cancelled, body mass index (BMI) was significantly higher (P < 0.001) in WHO 2 women compared with controls. Overall live birth rates were comparable (P = 0.9). Obese women suffering from WHO 2 anovulatory infertility are at an increased risk of having their IVF cycle cancelled due to insufficient response. Once oocyte retrieval is achieved, live birth rates are comparable with controls.

Aging women with polycystic ovary syndrome who achieve regular menstrual cycles have a smaller follicle cohort than those who continue to have irregular cycles

OBJECTIVE

To examine whether follicle loss due to ovarian aging is responsible for the occurrence of regular menstrual cycles in aging women with polycystic ovary syndrome (PCOS), the size of the FSH-sensitive follicle cohort was estimated by the exogenous follicle-stimulating hormone ovarian reserve test (EFORT) and related to the follicle count as measured by ultrasound.

DESIGN

Prospective study.

SETTING

Reproductive endocrinology unit of an academic medical center.

PATIENT(S)

Twenty-seven aging women with PCOS (35.8-49.4 years): 20 with regular menstrual cycles and 7 with oligomenorrhea or amenorrhea.

INTERVENTION(S)

EFORT and transvaginal ultrasound.

MAIN OUTCOME MEASURE(S)

Baseline (cycle day 2, 3, or 4) FSH, androstenedione (A), T, E(2), and inhibin B levels, the E(2) and inhibin B increment after the EFORT, and the follicle count.

RESULT(S)

After correction for the body mass index (BMI), the inhibin B increment was higher in the irregular menstrual group, but the E(2) increment did not differ significantly between the two groups. Ultrasound showed a median follicle count of 8.5 (4.0-18.0) in women with regular menstrual cycles (n = 16), compared with 18.0 (8.0-35.0) in irregularly menstruating women (n = 7). The follicle count was significantly correlated to the FSH-induced E(2) increment (r = 0.656) as well as to the inhibin B increment (r = 0.654). The regularly menstruating group was significantly older, had a higher basal FSH concentration, and had lower androgens than the irregularly menstruating group.

CONCLUSION(S)

The smaller follicle count, the older age, the higher FSH concentration, and the lower FSH-induced inhibin B increment found in women with PCOS and a regular menstrual cycle confirm that a decrease in the size of the follicle cohort due to ovarian aging is largely responsible for the regular menstrual cycles in aging PCOS women.

Activins, inhibins, and follistatins: from endocrinology to signaling. A paradigm for the new millennium

It has been 70 years since the name inhibin was used to describe a gonadal factor that negatively regulated pituitary hormone secretion. The majority of this period was required to achieve purification and definitive characterization of inhibin, an event closely followed by identification and characterization of activin and follistatin (FS). In contrast, the last 15-20 years saw a virtual explosion of information regarding the biochemistry, physiology, and biosynthesis of these proteins, as well as identification of activin receptors, and a unique mechanism for FS action-the nearly irreversible binding and neutralization of activin. Many of these discoveries have been previously summarized; therefore, this review will cover the period from the mid 1990s to present, with particular emphasis on emerging themes and recent advances. As the field has matured, recent efforts have focused more on human studies, so the endocrinology of inhibin, activin, and FS in the human is summarized first. Another area receiving significant recent attention is local actions of activin and its regulation by both FS and inhibin. Because activin and FS are produced in many tissues, we chose to focus on a few particular examples with the most extensive experimental support, the pituitary and the developing follicle, although nonreproductive actions of activin and FS are also discussed. At the cellular level, it now seems that activin acts largely as an autocrine and/or paracrine growth factor, similar to other members of the transforming growh factor beta superfamily. As we discuss in the next section, its actions are regulated extracellularly by both inhibin and FS. In the final section, intracellular mediators and modulators of activin signaling are reviewed in detail. Many of these are shared with other transforming growh factor beta superfamily members as well as unrelated molecules, and in a number of cases, their physiological relevance to activin signal propagation remains to be elucidated. Nevertheless, taken together, recent findings suggest that it may be more appropriate to consider a new paradigm for inhibin, activin, and FS in which activin signaling is regulated extracellularly by both inhibin and FS whereas a number of intracellular proteins act to modulate cellular responses to these activin signals. It is therefore the balance between activin and all of its modulators, rather than the actions of any one component, that determines the final biological outcome. As technology and model systems become more sophisticated in the next few years, it should become possible to test this concept directly to more clearly define the role of activin, inhibin, and FS in reproductive physiology.

The physiology and pathophysiology of inhibin, activin and follistatin in female reproduction

In the last 2 years, major advances have been made in the understanding of inhibin physiology. Discovery of an inhibin receptor and binding protein has expanded our knowledge of the mechanism whereby inhibin antagonizes activin action. Controlled experimental studies have clarified the regulation and physiology of inhibin A and inhibin B, providing evidence for their use as markers of ovarian function. Clinical studies continue to uphold the use of inhibin as a marker for ovarian cancer, but have not generally supported its use over standard prognostic markers in assisted reproductive technologies. Finally, ongoing work suggests alterations in inhibin and follistatin that may be linked to the pathophysiology of polycystic ovary syndrome. Thus, the mechanism of inhibin action and its role in normal and abnormal ovarian function continues to emerge.

Obesity and serum luteinizing hormone level have an independent and opposite effect on the serum inhibin B level in patients with polycystic ovary syndrome

OBJECTIVE

To elucidate whether the negative effect of obesity on the serum inhibin B level that we previously reported is specific or not to polycystic ovary syndrome (PCOS) and whether it may explain the wide interindividual variability in serum inhibin B levels found in patients with PCOS.

DESIGN

Prospective study.

SETTING

Reproductive endocrinology unit of an academic medical center.

PATIENT(S)

One hundred thirty-four consecutive patients with PCOS (mean age, 27.4 +/- 4.7 years; mean body mass index [BMI], 28.3 +/- 7.6 kg/m(2); BMI > 25, 53%) and in 78 control women (mean age, 30.1 +/- 4.1 years; mean BMI, 24.3 +/- 4.9; BMI > 25, 34%).

INTERVENTION

Blood sampling was performed in the early follicular phase in patients and in control women.

MAIN OUTCOME MEASURE(S)

BMI and waist circumference (WC), serum levels of inhibin B, LH, FSH, E(2), androstenedione, T, fasting insulin, and leptin were assessed in all subjects.

RESULT(S)

No difference was observed in the mean inhibin B level between patients and controls. The BMI and WC correlated negatively with inhibin B in patients with PCOS and in controls, with similar regression slopes, thus indicating that the influence of obesity on inhibin B is not specific to PCOS. In addition, we found a positive relationship between serum LH and inhibin B levels in PCOS. There was no significant interaction between the effects of BMI and LH on the serum inhibin B levels by analysis of variance (ANOVA). The mean serum inhibin B level in patients with PCOS with high serum LH (i.e., >the 90th percentile of LH in controls) was significantly higher than in those patients with normal LH or in controls. The highest mean inhibin B level was noted in nonobese patients with PCOS with high LH levels (121.0 +/- 51.2 pg/mL), while nonobese patients with PCOS with normal LH levels and obese patients with normal LH or high LH levels had similar mean levels (94.5 +/- 40.0, 84.9 +/- 34 and 91.6 +/- 51.7 pg/mL, respectively).

CONCLUSION(S)

We confirm that obesity has a negative effect on inhibin B serum level, which is not specific to PCOS. Obesity and excess LH, acting oppositely and independently on inhibin B production, may explain the discrepancies between the previous reports studying serum inhibin B level in patients with PCOS. Further work is required to elucidate the mechanisms underlying the antagonistic effects of LH and obesity on inhibin B production in patients with PCOS.

The influence of obesity on hyperandrogenism and infertility in the female

Although a critical mass of adipose tissue is essential for the normal development of female reproductive function, obesity has been shown to produce menstrual disturbances and subfertility. The severity of obesity and the distribution of fat tissue are important factors that influence the female reproductive system. The pathogenetic mechanistic links between them aren't clearly elucidated. Obese women, especially those with upper body obesity, have insulin resistance and hyperinsulinaemia, hyperandrogenaemia, increased peripheral aromatization of androgens to oestrogens, altered gonadotrophin secretion, decreased sex hormone binding globulin, decreased growth hormone (GH) and insulin like growth factor binding proteins (IGFBPs), increased leptin levels and altered neuroregulation of the hypothalamic-pituitary-gonadal axis. These have been considered as some of the links in the sequence of events of the disrupted ovulatory process. The mechanisms of these actions and their influence on female reproductive function are discussed below.

Obesity, polycystic ovary syndrome and anovulation--how are they interrelated?

Polycystic ovary syndrome remains a mystery with respect to its aetiology, consequences and management. There is an increasing emphasis on its familial origins although the genes involved are unknown. There are significant changes in risk profiles for cardiovascular disease but no clear clinical evidence of morbidity or mortality. There is evidence of improvement in insulin resistance or insulin sensitivity drugs but uncertainty about improvement in pregnancy outcomes. This review looks at the latest advances in understanding polycystic ovary syndrome, particularly in obesity.