Testosterone-induced downregulation of anti-Müllerian hormone expression in granulosa cells from small bovine follicles.

Polycystic ovary syndrome (PCOS) is characterized by the presence of hyperandrogenism and an increased follicular mass probably determined by deregulation of locally produced factors. Anti-Müllerian hormone (AMH) is a glycoprotein that inhibits follicular recruitment and determines the size of the follicular pool. To evaluate the role of androgens in the regulation of AMH expression in bovine granulosa cells from small follicles, granulosa cells from 3 to 4 mm follicles were isolated and incubated in basal culture media, or in media containing testosterone (T) at 10(-5)M, T 10(-8)M, or estradiol (E2) at 150 ng/ml for 48 h. AMH mRNA levels of these cells were determined using real-time PCR (RT PCR). AMH protein levels and E2 were determined in cell-conditioned media. A 3.4-fold decrease in AMH mRNA levels was observed in granulosa cells exposed to T 10(-5)M (P = 0.03, n = 5), but not in cells exposed to T 10(-8)M. AMH protein levels showed a 1.8-fold reduction in cell-conditioned media from cells exposed to T 10(-5)M (P = 0.01, n = 5), without significant changes in the group exposed to T 10(-8)M. Cells treated with E2 150 ng/ml showed no change in AMH protein levels. We propose that AMH expression is modulated by androgens in bovine granulosa cells from small follicles. Thus, it is possible to speculate that androgens, by inhibiting AMH expression, may promote follicle recruitment, increasing the early growing follicular pool. This new mechanism may have implications for the understanding of PCOS pathophysiology.