The effect of estradiol on granulosa cell responses to FSH in women with polycystic ovary syndrome

BACKGROUND The influence of estradiol (E2) on granulosa cell (GC) function has not been tested clinically in women with polycystic ovary syndrome (PCOS). The objective of this study is to determine if E2 influences GC responses to FSH in women with PCOS. METHODS This is a two phase, single cohort study conducted over a 2-year period at a single academic center. Nine women with PCOS according to NIH criteria. In Phase 1, FSH stimulation of GC responses as measured by E2 and Inhibin B (Inh B) were assessed before and at 5 and 6 weeks after GnRH agonist administration. In Phase 2, the same protocol was employed with the addition of an aromatase inhibitor (letrozole, LET) administered daily beginning at week 4 for 2 weeks. RESULTS In Phase 1, recovery of FSH, E2 and Inh B from ovarian suppression occurred at 5 and 6 weeks after GnRH agonist injection and preceded resumption of LH and androgen secretion. In Phase 2, hormone recovery after GnRH agonist was characterized by elevated FSH and suppressed E2 levels whereas recovery of LH and androgen levels were unchanged. In Phase 1, FSH stimulated E2 and Inh B responses were unaltered during recovery from ovarian suppression. In Phase 2, E2 and Inh B fold changes after FSH were significantly reduced at weeks 5 (p < 0.04) and 6 (p < 0.01), respectively. CONCLUSION In anovulatory women with PCOS, chronic, unopposed E2 secretion may contribute, at least in part, to enhanced ovarian responsiveness to FSH. TRIAL REGISTRATION NCT02389088.