Objective: To determine the nature of bioactive FSH secretion in anovulatory women with polycystic ovary syndrome (PCOS) and its modulation by luteal levels of E2 and P.
Design: Interventional and observational study.
Setting: Academic clinical research center.
Patient(s): Five patients with PCOS.
Intervention(s): Treatment for 21 days with luteal levels of E2 and P.
Main outcome measures: Serum levels of immunoreactive LH, immunoreactive FSH, bioreactive FSH, and the FSH isoform distribution pattern. Blood was sampled frequently and GnRH testing was done on day 0 (before treatment), days 10 and 20 (during treatment), and day 28 (7 days after treatment).
Result(s): Treatment with E2 and P suppressed circulating immunoreactive LH and immunoreactive FSH but not bioreactive FSH. Anovulatory women with PCOS showed a predominantly acidic pattern of FSH isoform distribution. Treatment with E2 and P shifted the distribution profile of FSH isoforms to the less acidic. After cessation of E2-P treatment, FSH reverted to its pretreatment pattern of distribution.
Conclusion(s): Resumption of follicular growth after luteal replacement of E2 and P in anovulatory women with PCOS may be related to the reduction in the elevated LH/FSH ratio and accompanying changes in the FSH signal.