Inhibin A, inhibin B and activin A concentrations in follicular fluid fromwomen with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is characterized by arrested follicle deve lopment at the early antral stage. Alterations in inhibin production by dev eloping follicles could be involved in PCOS by suppressing follicle stimula ting hormone concentrations during the follicular phase of the menstrual cy cle as well as by increasing thecal androgen production. Inhibin B appears to be more important than inhibin A during the follicular phase; however, t here are no data regarding the follicular fluid concentrations of inhibin B in PCOS, The purpose of this study was to compare inhibin A, inhibin B and activin A concentrations in the follicular fluid from regularly cycling wo men and women with PCOS, Inhibin A, inhibin B and activin A were measured i n the follicular fluid of 4-7 mm follicles from PCOS ovaries and size-match ed follicles from normally cycling women by specific and sensitive two-site enzyme-linked immunosorbent assays. In both control and polycystic ovaries , inhibin B was approximately Ill-fold higher than activin A and more than 100-fold higher than inhibin A. There was no difference in activin A concen trations between PCOS and control follicles, In control ovaries, the inhibi n B and inhibin A concentrations in dominant follicles were significantly h igher than in cohort follicles. While inhibin A concentrations were lower i n PCOS follicles than in normal cohort follicles, there was no difference i n inhibin B concentrations between PCOS follicles and normal cohort follicl es, These data are consistent with the concept that inhibin B is the physio logically most important form of inhibin during the follicular phase of the menstrual cycle and indicate that PCOS is not associated with increased in hibin B concentrations in follicular fluid.