Comparison of Follicle-Stimulating-Hormone-Stimulated Dimeric Inhibin and Estradiol Responses as Indicators of Granulosa Cell Function in Polycystic Ovary Syndrome and Normal Women

Abstract

CONTEXT: Follicular phase secretion of inhibin B, like that of estradiol (E(2)), correlates with the quantity and quality of developing follicles. However, it has not been established whether inhibin B responses to gonadotropin stimulation parallel those of E(2) as a reflection of granulosa cell functional capacity. OBJECTIVE: Our objective was to determine whether inhibin B responses to FSH stimulation are similar to those of E(2) in women with polycystic ovary syndrome (PCOS) and normal women. DESIGN AND SETTING: We conducted a prospective study to compare ovarian responses in two groups of women at a general clinical research center in a tertiary academic medical center. PATIENTS: Women with PCOS, 18-35 yr (n = 19), and normal ovulatory controls, 18-35 yr (n = 7), were recruited for study. INTERVENTIONS: Serum samples were measured over a 24-h period after an iv injection of recombinant human FSH, 150 IU. MAIN OUTCOME MEASURES: Serum E(2), inhibin A, and inhibin B responses after FSH administration were assessed. RESULTS: In PCOS women, the 24-h production of inhibin B and E(2) after FSH was significantly greater than that of normal controls. Within the PCOS group, the fold change in inhibin B was significantly greater than that of E(2). Inhibin A responses between groups were similar and of markedly lower magnitude. CONCLUSIONS: FSH-stimulated inhibin B responses may be employed to assess the functional capacity of granulosa cells in PCOS and normal women.