Dimeric inhibins and activin A in human follicular fluid and oocyte-cumulus culture medium.

The concentrations of inhibin A, inhibin B and activin A in follicular fluid and oocyte culture medium were analysed to investigate the production of these peptide hormones by ovarian granulosa cells and oocyte-cumulus complexes, as well as their potential as possible biochemical markers for oocyte quality and fertilizing capacity. Follicular fluids were collected from individual follicles during oocyte retrieval for in-vitro fertilization (IVF). Oocyte-cumulus culture media were collected after in-vitro insemination. The concentrations of dimeric inhibin A, inhibin B and activin A were measured using two-site enzyme-linked immunosorbent assays in the follicular fluid and matched oocyte culture medium. Hormone concentrations were compared with oocyte quality and fertilizing capacity. The concentration of inhibin A in follicular fluid increased while that of inhibin B decreased with increasing follicle size. Follicular fluid concentrations of inhibin A inhibin B and activin A were not significantly different in follicles with differing oocyte quality. Oocyte culture medium concentrations of activin A were significantly higher in morphologically good quality oocytes. There was no relationship between the concentrations of the three hormones and oocyte fertilizing capacity. This study confirms that follicular fluid concentrations of inhibin A may prove to be a marker of follicular growth and maturation. Higher concentrations of activin A produced by good quality oocyte-cumulus complexes suggest that activin A may play a role in oocyte maturation.     

Ovary: Follistatin concentrations in follicular fluid of normal and polycystic ovaries

Follistatin (FS) is an activin/inhibin binding protein whichis believed to act in an autocrine/paracrine manner to regulategrowth and differentiation. Although FS has been identifiedin human follicular fluid, it remains unclear how its concentrationchanges during selection and atresia, and what the concentrationsof FS are in follicles of women with polycystic ovary syndrome(PCOS). Towards this goal, we have measured by radioimmunoassaythe concentrations of FS in follicular fluid obtained from dominantand atretic cohort follicles of normal cycling women, preovulatoryfollicles of in-vitro fertilization (IVF) patients, and smallGraafian follicles of patients with PCOS. In all cases, thefollicular fluid concentration of FS was much higher (100-fold)than that reported in serum. The FS concentrations (ng/ml) were203 ± 42 (normal dominant), 185 ± 17 (atreticcohort), 185 ± 5 (IVF), and 250 ± 14 (PCOS). Therewas no statistical difference between these mean values of FS.Further, there were no significant correlations between thefollicular fluid concentrations of FS and the concentrationsof oestradiol, progesterone, or androstenedione. These resultsindicate that human Graafian follicles, regardless of whetherthey are healthy or atretic, normal or PCOS, contain high steady-stateconcentrations of FS in the micro-environment. Collectively,these data fit with the hypothesis that major increases anddecreases in the concentration of FS in the micro-environmentmay not play a key role in the mechanisms of selection, atresia,and PCOS in women. The possibility of regulation of intrinsicactivin and inhibin activity through FS binding is discussed.     

Inhibin A, inhibin B and activin A in follicular fluid of infertile women with tubal damage, unexplained infertility and emdometriosis

PROBLEM: To measure and compare concentrations of inhibin A, inhibin B, activin A and oestradiol in the follicular fluid of women with endometriosis, tubal damage and unexplained infertility with oocyte quality and fertilising capacity. Also, to assess whether impaired follicular function in women with endometriosis might be related to altered inhibin or activin concentrations and whether this correlated. METHOD OF STUDY: Follicular fluids were collected from individual follicles during oocyte retrieval for in vitro fertilisation (IVF) in natural cycles. Inhibin A, inhibin B and activin A were measured using two-site enzyme immunoassay, and oestradiol was assayed by fluoro-immunometric method. RESULTS: Follicular fluid inhibin A levels were found to be significantly higher in women with endometriosis. Inhibin A was directly correlated with follicle size. There was no correlation between the levels of inhibin A, inhibin B, activin A and oocyte quality or fertilising capacity in the three groups of women. CONCLUSIONS: Follicular fluid concentration of inhibin A is elevated in follicles of women with endometriosis and is positively correlated with follicle maturation. However, we were unable to demonstrate any association between the follicular fluid concentrations of inhibin A, inhibin B, activin A or oestradiol and the quality and fertilisation capacity of oocytes in women with tubal damage, unexplained infertility or endometriosis.     

Inhibin A, inhibin B and activin A in the follicular fluid of regularly cycling women

Recent measurements of circulating inhibin A and inhibin B concentrations indicate that inhibin B may play an important role in the selection of dominant follicles. The concentrations of inhibin A, inhibin B and activin A were measured in the follicular fluids of 61 individual follicles (4.8-20 mm in diameter) from 47 regularly cycling women using specific two-site enzyme-linked immunosorbent assays. The microenvironment of each follicle was characterized by measuring follicular fluid androstenedione and oestradiol concentrations. The mean activin A concentrations were < 8 ng/ml for follicles of all sizes (4-17 mm). Inhibin A concentrations were < 1 ng/ml in follicles < 6 mm, and progressively increased to concentrations > 50 ng/ml in follicles > or = 13 mm. Follicles with androstenedione/oestradiol ratios < or = 4 had higher concentrations of inhibin A than follicles with androstenedione/oestradiol ratios > 4. Inhibin B concentrations were higher than inhibin A concentrations in all follicles, increasing from 19.2 +/- 8.3 ng/ml in 4 mm follicles to 409 +/- 9.6 ng/ml in 13 mm follicles and then declining to 275 +/- 47 ng/ml in 17 mm follicles. These results support the hypothesis that inhibin B may play a more important paracrine role in developing follicles and a greater regulatory role with respect to follicle stimulating hormone (FSH) secretion than inhibin A.      

Healthy women and patients with endometriosis show high concentrations of inhibin A, inhibin B, and activin A in peritoneal fluid throughout the menstrual cycle

Inhibin A, inhibin B, and activin A are growth factors which play local autocrine/paracrine roles in reproductive tissues. Since peritoneal fluid hormone content may reflect in part ovarian and endometrial secretory activities, the present study aimed to evaluate: (i) whether inhibin alpha-, activin betaA- and betaB-subunits, and activin receptor type II and type IIB mRNA are expressed in peritoneal tissues; (ii) expression and secretion of inhibin A and B, and activin A in cultured endometriotic cells; and (iii) concentrations of inhibin A and B, and activin A in serum and in peritoneal fluid in healthy women and in patients with endometriosis throughout the menstrual cycle. A group of women (n = 72) was recruited at laparoscopy for infertility investigation and divided into two groups: (i) control healthy women (n = 35), (ii) women with endometriosis (n = 37). Both groups were subdivided according to the follicular and luteal phase of the menstrual cycle. At the time of laparoscopy, specimens of peritoneal tissues were collected from three healthy women, while endometriotic tissue samples were collected and cultured from three women with endometriosis. Peritoneal tissues and cultured endometriotic cells expressed inhibin alpha-, activin betaA-, and betaB-subunits, and activin receptors mRNAs; in addition, inhibin-related proteins were measurable in culture medium. In healthy women, inhibin A and B, and activin A concentrations in peritoneal fluid were significantly higher than in serum (P < 0.001), at both phases of the menstrual cycle. Peritoneal inhibin A and B, and activin A concentrations were not significantly different between healthy women and patients with endometriosis, either when evaluated according to the degree of the disease and/or to the phase of the menstrual cycle. In conclusion, the findings that high concentrations are present in peritoneal fluid and that menstrual cycle-related changes occur suggest that reproductive organs may contribute to inhibin-related proteins in peritoneal fluid.      

Serum concentrations of dimeric inhibins, activin A, gonadotrophins and ovarian steroids during the menstrual cycle in older women

The transition from regular ovarian cyclicity to menopause is associated with a rise in the circulating concentrations of follicle stimulating hormone (FSH), despite the maintenance of serum oestradiol concentrations during the perimenopause. The aim of this study was to compare the pattern of secretion of dimeric inhibins, activin A, gonadotrophins and steroids in regularly cycling women of 40-50 years with normal and raised early follicular phase serum FSH concentrations and young women (25-33 years) during the menstrual cycle. Blood samples were taken prospectively almost daily throughout the menstrual cycle. Women recruited were classified into three groups: (i) older women with normal FSH [(ON-FSH), day 3 FSH <8 mIU/ml, n = 10]; (ii) older women with raised FSH [(R-FSH), day 3 FSH >8 mIU/ml, n = 6] and (iii) young normal FSH (YN-FSH) women, age 25-32 years (n = 6). Cyclic patterns of serum inhibins and activin A were similar in the ON-FSH and YN-FSH groups. The R-FSH group had significantly lower concentrations of inhibin A prior to the luteinizing hormone (LH) surge and in the mid-luteal phase and lower concentrations of inhibin B in the early follicular phase compared with the ON-FSH group. Serum concentrations of activin A, progesterone and oestradiol were similar in all three groups. It is concluded from this study that the rise in early follicular phase serum FSH in older women is associated with a decrease in circulating concentrations of inhibin B in the early follicular phase. However, lower circulating concentrations of inhibin A in the luteal phase of the R-FSH group may also contribute to the rise in early follicular phase FSH concentrations during the menstrual cycle, although further studies with larger numbers are required to confirm this observation.     

Endocrinology: Insulin-like growth factor binding proteins in a natural pre-ovulatory follicle from a woman with polycystic ovary syndrome

Insulin-like growth factor binding protein (IGFBP) concentrationsin the follicular fluid of ovarian follicles have been shownto correlate with dominance and atresia. IGFBP-2 and IGFBP-4are increased in atresia, and IGFBP-3 is decreased in dominantfollicles. The purpose of this study was to compare the IGFBPconcentration in follicular fluid from a natural pre-ovulatoryfollicle of a woman with polycystic ovarian syndrome (PCOS)with other PCOS follicles and dominant follicles from normallycycling women. Follicular fluid was collected from 5–7mm diameter follicles and a natural pre-ovulatory follicle fromwomen with PCOS, and healthy and atretic follicles from normalwomen. The IGFBP profiles were analysed using Western ligandblotting. The IGFBP concentrations in the 5–7 mm diameterfollicles from the polycystic ovaries containing a pre-ovulatoryfollicle were similar to those in follicles from other womenwith PCOS, and comparable with androgenic cohort follicles fromnormal women. In particular, the IGFBP-2 and IGFBP-4 concentrationswere elevated significantly compared with the oestrogenic cohortfollicles. The concentrations of all IGFBP detected in the follicularfluid from the PCOS pre-ovulatory follicle were significantlyless than those of the 5–7 mm diameter follicles fromthe same subject. The IGFBP concentrations were within the rangeof normal dominant follicles, and IGFBP-2 and IGFBP-3 were atthe lower end of the normal range. The results indicate thatthe PCOS pre-ovulatory follicle contained a normal pattern ofIGFBP expression even though the other follicles exhibited apattern typical of PCOS. These data support the hypothesis thatdecreased concentrations of IGFBP, in particular IGFBP-3, maybe involved in selection of the dominant follicle, and thatwhen a spontaneous pre-ovulatory follicle develops in PCOS,the underlying cause of the polycystic ovaries is not resolvedbut the rest of the ovary remains polycystic.     

Serum inhibins,estradiol, progesterone and FSH in surgical menopause: a demonstration of ovarian pituitary feedback loop in women

BACKGROUND: The objective of this study was to confirm the source and study the acute changes and relationship between inhibins and FSH at surgical menopause. METHODS: Regularly cycling women (42-47 years; n = 10) undergoing bilateral oophorectomy for non-ovarian pathology were recruited for this study. One blood sample was taken before surgery and after removal of the ovaries, samples were taken every 15 min up to 1 h, hourly up to 6 h, after 12 h and daily during the hospital admission (3 days). RESULTS: There were five women in the follicular phase and five women in the luteal phase of the cycle. For women in both phases, levels of inhibin A, inhibin B, estradiol (E(2)) and progesterone decreased after the removal of the ovaries. Serum FSH levels started to rise after 12 h in both follicular and luteal phase women after the surgical menopause. Correlation analysis showed that inhibin A and E(2) were significantly negatively correlated in both phases with FSH concentration. Inhibin B had a negative correlation in the follicular phase and progesterone had a negative correlation in the luteal phase. CONCLUSIONS: This study showed that ovarian inhibin A and B were cleared from the circulation within 12 h of oophorectomy, whereas E(2) and progesterone remain in the circulation for longer. Negative correlation between FSH, inhibin A and inhibin B suggests that inhibins may contribute to the observed early rise in FSH after the surgical menopause.     

Inhibin and activin secretion during murine preantral follicle culture and following HCG stimulation.

BACKGROUND: Isolation and culture to antral stage of mouse preantral follicles provides an ideal system for investigating the endocrinology of follicular development to maturity. METHODS: The release of inhibin A, inhibin B, pro-alphaC and activin A was measured at specific time-points throughout an in-vitro culture period of 8 days. At the end of culture, follicles were induced to ovulate in vitro by the addition of HCG and the resulting hormone secretion studied both at 20 h and at 6 h intervals. RESULTS: During the preovulatory culture period, the concentrations of inhibin A, B, pro-alphaC and activin A increased significantly. Compared with control, there was a significant decline at 24 h in the concentrations of inhibin A [P < 0.001; 216 +/- 47 versus 823 +/- 110 arbitrary mouse units (amu)/ml], inhibin B (P < 0.01; 131 +/- 23 versus 361 +/- 45 amu/ml) and pro-alphaC (P < 0.001; 14 +/- 5 versus 1198 +/- 212 pg/ml). In contrast, there was a significant increase in the concentration of activin A (P < 0.001; 1.32 +/- 0.04 versus 0.34 +/- 0.03 ng/ml). CONCLUSIONS: These data provide clear evidence of a profound change in the relative secretion rates of inhibin and activin relative to ovulation and suggest that the principal role of activin A may be at time of ovulation rather than during follicular development.     

Circulating follistatin concentrations are higher and activin concentrations are lower in polycystic ovarian syndrome

Familial polycystic ovarian syndrome (PCOS) has been proposed to be linked to a site near the follistatin gene. We studied the concentrations of circulating follistatin, activin A and inhibin B in well-characterized subjects with PCOS (n = 108) and controls without PCOS (n = 20). Mean (+/- SEM) concentrations of follistatin were higher (P < 0.05) in PCOS (0.27 +/- 0.03 ng/ml) than controls (0.15 +/- 0.02 ng/ml) and activin A were lower (P < 0.05) in PCOS (0.20 +/- 0.01ng/ml) than controls (0.24 +/- 0.02 ng/ml). Inhibin B concentrations were not different between the two groups: PCOS (0.06 +/- 0.01ng/ml), and controls (0.06 +/- 0.01ng/ml). It is proposed that higher concentrations of follistatin with lower concentrations of activin A may relate to follicular development not proceeding beyond 8-10 mm and may be partly responsible for the lack of pre-ovular follicle development in PCOS.     

Absent biologically relevant associations between serum inhibin B concentrations and characteristics of polycystic ovary syndrome in normogonadotrophic anovulatory infertility.

BACKGROUND: Dominant follicle selection is disturbed in normogonadotrophic anovulatory infertility [World Health Organization (WHO) 2] and remaining early antral follicles are either healthy or atretic. This study was conducted to investigate whether inhibin B serum concentrations (produced by healthy small antral follicles) represent the extent of ovarian abnormalities in WHO 2 women and patients with polycystic ovarian syndrome (PCOS), constituting a subgroup of WHO 2 patients. METHODS AND RESULTS: Ultrasonographic and endocrine characteristics in 379 WHO 2 patients and 30 normo-ovulatory controls were compared. In the WHO 2 patients, the PCOS subgroup and the controls, inhibin B concentrations were similar. Inhibin B concentrations were weakly but significantly correlated with the total number of ovarian follicles (r = 0.282; P < 0.001), LH (r = 0.347; P < 0.001), and testosterone (r = 0.269; P < 0.001) but not with serum oestradiol concentrations (r = 0.057). Most (71%) patients with elevated inhibin B also presented with increased concentrations of LH and/or hyperandrogenaemia. In a subgroup of 190 subjects, classified as PCOS based on hyperandrogenaemia and polycystic ovaries, elevated inhibin B concentrations were found in 23% of cases. Aforementioned correlations were similar in PCOS as in WHO 2 patients. CONCLUSION: In conclusion, inhibin B serum concentrations are normal in WHO 2 and PCOS women, suggesting a normal number of healthy early antral follicles despite increased overall follicle numbers in PCOS.     

Day 5 inhibin B serum concentrations as predictors of assisted reproductive technology outcome in cycles stimulated with gonadotrophin-releasing hormone agonist-gonadotrophin treatment

The present study investigates the usefulness of inhibin A, inhibin B and serum oestradiol concentrations obtained in the fifth day of gonadotrophin therapy in predicting ovarian response and assisted reproductive treatment outcome in women undergoing ovarian stimulation under pituitary desensitization. A total of 80 women undergoing their first cycle of in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatment were studied. Twenty consecutive cycles which were cancelled because of a poor follicular response were initially selected. As a control group, 60 women were randomly selected from our assisted reproductive treatment programme matching by race, age, body mass index, and indication for IVF/ICSI to those in the cancelled group. For each cancelled cycle, three IVF/ICSI women who met the matching criteria were included. Basal follicle stimulating hormone (FSH) concentrations were significantly higher in the cancelled than in the control group, whereas basal inhibin B was significantly higher in the latter. Basal oestradiol concentrations were similar in both groups of patients. On day 5 of gonadotrophin therapy serum concentrations of oestradiol, inhibin A and inhibin B were significantly lower in the cancelled group as compared with controls. Logistic regression analysis showed that the association for day 5 inhibin B (with a predictive value of ovarian response of 91.03%) with cancellation rate was significant, independent of, and stronger than, the effects of any other hormone variable investigated. In addition, day 5 inhibin B concentrations were correlated directly with parameters of ovarian response, ovum retrieval and oocyte and fertilization outcome. However, day 5 inhibin B was not a better predictor of pregnancy than the other hormone variables studied on this day. It is concluded that inhibin B concentrations obtained early in the follicular phase during ovarian stimulation under pituitary suppression for assisted reproductive treatment are highly predictive of ovarian response.     

Elevated FSH concentrations in imminent ovarian failure are associated with higher FSH and LH pulse amplitude and response to GnRH

Imminent ovarian failure (IOF) in women is characterized by regular menstrual cycles and elevated early follicular phase FSH. This study explored underlying neuroendocrine causes of elevated FSH concentrations on day 3 of the menstrual cycle. The characteristics of episodic secretion of FSH and LH, the pituitary response to gonadotrophin-releasing hormone (GnRH), plasma oestradiol, and dimeric inhibin A and inhibin B on day 3 were compared in 13 women with elevated FSH concentrations (>10 IU/l) and 16 controls. FSH amplitudes were higher in the IOF group than in the controls (P < 0. 0001). The FSH pulse frequency did not differ between groups. The FSH response to GnRH was higher in the IOF patients than in the controls (P < 0.0001). Mean LH, LH amplitude and LH response to GnRH were higher in the IOF group, but LH pulse frequency did not differ between the groups. Concentrations of inhibin A and inhibin B were lower in the IOF group, while oestradiol showed no differences. We concluded that in women with IOF, the pituitary is more sensitive to GnRH. This leads to higher FSH and LH pulse amplitudes which underlie the elevated FSH concentrations in the early follicular phase.     

Follistatin and activin A serum concentrations in obese and non-obese patients with polycystic ovary syndrome.

BACKGROUND: Activin promotes ovarian follicular development, inhibits androgen production and increases FSH and insulin secretion. Follistatin, an activin-binding protein, neutralizes activin bioactivity. Therefore, a decrease in the ratio of activin/follistatin might encourage characteristic features of polycystic ovary syndrome (PCOS). We investigated whether women with PCOS showed disordered follistatin and/or activin serum concentrations. METHODS: The study group included 24 obese and 20 non-obese (body mass index vertical line and <27 kg/m2 respectively) clomiphene-failure PCOS patients. The control group included 16 obese and 46 non-obese patients with normal ovulatory cycles. Blood samples were obtained from the patients on day 3-5 of a progesterone-induced or spontaneous cycle and were assayed for LH, FSH, testosterone, 17-hydroxy-progesterone, androstenedione, follistatin, activin A, fasting glucose and insulin. RESULTS: Follistatin concentrations were comparable between obese and non-obese PCOS patients (mean +/- SE; 1171 +/- 103 and 1045 +/- 159 pg/ml respectively) and significantly higher than their respective controls (628 +/- 61 and 592 +/- 49 pg/ml, P < 0.0001 and P < 0.02 respectively). Activin A concentrations were comparable between the four groups (590 +/- 35, 513 +/- 74, 661 +/- 87 and 595 +/- 43 pg/ml in obese and non-obese PCOS and controls respectively). Stepwise regression analyses for relationships between follistatin or activin A levels and all other variables indicated that follistatin was significantly and independently positively affected by PCOS (P < 0.0001), age (P < 0.02), androstenedione (P < 0.03) and weight (P < 0.05). Activin A was significantly and independently negatively affected by PCOS (P < 0.003) and FSH (P < 0.03), and positively affected by weight (P < 0.009) and androstenedione (P < 0.02). CONCLUSIONS: Serum follistatin is increased in PCOS patients, regardless of obesity. PCOS is the most significant variable that relates to high follistatin and low activin A serum concentration. A high follistatin/activin ratio could well contribute to the pathophysiology of PCOS.     

Follicular fluid concentration of leukaemia inhibitory factor is decreased among women with polycystic ovarian syndrome during assisted reproduction cycles

BACKGROUND: The possibility that a specific cytokine profile could be detected in the ovaries of patients with polycystic ovarian syndrome (PCOS) was investigated. METHOD: Enzyme-linked immunosorbent assay (ELISA) or bioassays were used to assess the concentrations of leukaemia inhibitory factor (LIF), tumour necrosis factor, interleukin 11, gamma interferon, progesterone and oestradiol in follicular fluids from preovulatory follicles collected after ovarian stimulation from 15 PCOS patients, 15 infertile control patients with regular cycles, and 8 oocyte donors. RESULTS: LIF and progesterone concentrations were significantly lower in the follicular fluid of PCOS patients (LIF median: 265 pg/ml) compared with controls (LIF median: 816 pg/ml); LIF and progesterone follicular fluid concentrations were correlated (r = 0.720, P = 0.0001). The LH/FSH ratio was negatively correlated with LIF concentrations (r = - 0.714, P = 0.0075). Although the PCOS and control patients did not differ significantly in age, ovarian reserve or IVF indication, the implantation rate was significantly lower among the women with PCOS (IR = 9 versus 21%, P = < 0.01). CONCLUSION: The specific cytokine profile of the PCOS patients is probably related to the lower implantation rate since follicular fluid LIF appears to function as an embryotrophic agent.     

The number of antral follicles in normal women with proven fertility is the best reflection of reproductive age

BACKGROUND: The purpose of this study was to compare the predictive capacity of several markers of reproductive age in normal women. METHODS: Healthy female volunteers (n = 162) aged 25-46 years with proven, normal fertility and regular menstrual cycles were recruited. In this selected group, chronological age was assumed to approximate reproductive age and, therefore, was taken as the proxy-variable for reproductive age. The number of antral follicles with 2-10 mm diameter, total ovarian volume, total follicular volume, mean follicular volume, and volume of either the smallest or largest ovary were estimated by transvaginal sonography of the ovaries. Serum levels of early follicular FSH, estradiol and inhibin B, as well as the response of estradiol and inhibin B to exogenous GnRH agonist administration (GAST), were also evaluated. RESULTS: Regression analysis revealed that the antral follicle number showed the highest correlation with age (r = -0.68, P = 0.001), and explained 46% of its variance. All other variables, except inhibin B, were moderately correlated with age. Responses of estradiol and inhibin B to the GnRH agonist were moderately correlated with age, but highly correlated with the number of antral follicles. CONCLUSIONS: It is concluded that the number of antral follicles has the closest association with chronological age in normal women with proven fertility. As stimulated estradiol and inhibin B clearly reflect the size of the antral follicle cohort, the GAST may be considered the second best single test to predict reproductive age.     

Ultrasound examination of polycystic ovaries: is it worth counting the follicles?

BACKGROUND: This study revisited the ultrasonographic diagnostic criteria of polycystic ovary syndrome (PCOS) and studied the relationship between the major hormonal and metabolic features of PCOS and the follicle number per ovary (FNPO). METHODS: This prospective study included 214 women with PCOS compared with 112 women with normal ovaries. Main clinical, biological and ultrasonographic markers of PCOS were assessed during the early follicular phase. RESULTS: The mean FNPO of follicles 2-5 mm in size was significantly higher in polycystic ovaries than in controls, while it was similar within the 6-9 mm range. Setting the threshold at 12 for the 2-9 mm FNPO offered the best compromise between specificity (99%) and sensitivity (75%). Within the 2-5 mm follicular range, we found significant positive relationships between the FNPO and androgens. The FNPO within the 6-9 mm range was significantly and negatively related to body mass index and fasting insulin serum level. CONCLUSIONS: We propose to modify the definition of polycystic ovaries by adding the presence of > or =12 follicles measuring 2-9 mm in diameter (mean of both ovaries). Also, our findings strengthen the hypothesis that the intra-ovarian hyperandrogenism promotes excessive early follicular growth and that further progression cannot proceed normally because of hyperinsulinism and/or other metabolic influence linked to obesity.     

Changes in serum inhibin, activin and follistatin concentrations during puberty in girls

Serum concentrations of inhibin A, inhibin B, activin A and follistatin were determined using two-site enzyme-linked immunosorbent assays (ELISA) during pubertal ovarian development in 28 girls and five follicular phase women. Blood obtained every 15 to 20 min overnight was pooled for peptide determination. Serum inhibin A concentrations increased in mid puberty, exhibiting positive correlations with bone age (r = 0.527, P = 0.0016) and oestradiol concentrations (r = 0.581, P = 0.0005). Inhibin B concentrations peaked in mid puberty and declined thereafter, but remained greater than concentrations seen in prepubertal girls, and correlating positively with oestradiol (r = 0.362, P = 0.046) and follicle stimulating hormone (FSH) concentrations (r = 0.369, P = 0.038). Total activin A concentrations did not vary significantly across pubertal stages. Total follistatin concentrations, determined by radioimmunoassay, decreased with advancing puberty, exhibiting negative correlations with bone age (r = -0.634, P = 0.0001) and oestradiol concentration (r = -0.687, P = 0.0001). Follistatin concentrations determined by an ELISA specific for follistatin 288 were greatest in mid-pubertal girls, but concentrations in late puberty were less than those in early puberty. The free follistatin assay indicated that all circulating follistatin was activin-bound. These results suggest that significant changes in serum concentrations of FSH-regulatory peptides accompany the onset of puberty.     

High concentrations of inhibin A and inhibin B in ovarian serous cystadenoma: relationship with oestradiol and nitric oxide metabolites

Inhibin production has been demonstrated in malignant epithelial ovarian tumours, but secretion of inhibins by benign cystadenoma has not yet been reported. The present study evaluated the concentrations of inhibin A and inhibin B and the relationship with oestradiol and nitric oxide metabolites in fluid collected from benign ovarian serous cystadenomas (n = 15). In addition, follicular fluid samples (n = 14) from women with regular ovulatory cycles undergoing ovarian stimulation for IVF were studied as a reference group. High concentrations of inhibin A (median = 89.3 ng/ml) and inhibin B (median = 116.1 ng/ml) were found in the cystic fluid of ovarian serous cystadenomas. These inhibin concentrations were even higher than in follicular fluid of stimulated follicles (inhibins A and B = 41.2 and 46.8 ng/ml respectively; P: < 0.001), whereas oestradiol was approximately 18-fold lower in cystic fluid than in follicular fluid (median = 34 versus 622 pg/ml, P: < 0.001). In ovarian cysts, the concentrations of inhibin A and oestradiol were inversely correlated (r = -0.678, P: = 0.008). Cystic fluid samples containing the highest concentrations of NO(2)(-)/NO(3)(-) (45-60 micromol/l) had lower inhibin A and higher oestradiol concentrations than those samples containing lower concentrations (10-25 micromol/l) of NO(2)(-)/NO(3)(-). It is concluded that high amounts of dimeric inhibins are present in ovarian serous cystadenoma. The source of inhibins and the determinants of the inverse association of inhibin A with oestradiol and nitric oxide remain to be determined.     

Inhibin and renin in follicular fluids of patients with one or two ovaries stimulated with a GnRH agonist and gonadotrophins

Follicular fluids from eight patients with one ovary and from ten patients with two ovaries were investigated for bioactive inhibin, total renin, oestradiol (E2) and progesterone (P4) concentrations. Four follicular fluids were pooled per patient before assessment. All women had been stimulated similarly using a protocol including a GnRH agonist, HMG and HCG. Renin levels were significantly lower and P4 significantly higher in pools of follicular fluid from patients with one ovary, whereas inhibin and E2 concentrations were similar in both patient groups. A significant negative correlation was found in the pools of follicular fluid between inhibin and E2 in both groups. These results suggest a role for inhibin and renin in the paracrine and autocrine control of stimulated follicular development.