The rate of in vitro maturation of primary follicles from adult mice and the quality of oocytes is improved in the absence of anti-mullerian hormone.

Anti-Müllerian hormone (AMH) inhibits the recruitment of primordial follicles into the growing pool, but its role in primary and secondary follicles is not clear. We isolated primary follicles from the ovaries of 9- to 10-week old mice and examined whether AMH affected follicular development. Follicles were matured in media that was prepared using unsexed fetal bovine serum (FBS) or female FBS (FFBS) with or without added AMH for approximately 2 weeks and maturation rates to secondary follicles and metaphase II (MII) oocytes were measured by standard morphological criteria. Rates of parthenogenetic activation and in vitro fertilization (IVF) were assessed by cleavage and blastocyst development, respectively. Whereas addition of AMH blocked primary to secondary follicle transition, the primary to secondary and secondary to MII follicle maturation rates was significantly improved with FFBS. Folliculogenesis resumed once AMH was removed from the media of the arrested primary follicles. The rates of IVF and parthenogenesis of oocytes after in vitro maturation (IVM) without AMH were also improved compared to controls. The results indicate that removal of AMH from culture conditions during IVM from primary follicular stages should be considered to improve outcome.