Anti-Müllerian Hormone Inhibits FSH-Induced Cumulus Oocyte Complex In Vitro Maturation and Cumulus Expansion in Mice

Anti-Müllerian hormone (AMH) is secreted by the ovaries of female animals and exerts its biological effects through the type II receptor (AMHR2). AMH regulates follicular growth by inhibiting the recruitment of primordial follicles and reducing the sensitivity of antral follicles to FSH. Despite the considerable research on the actions of AMH in granulosa cells, the effect of AMH on the in vitro maturation of oocytes remains largely unknown. In the current study, we showed that AMH is only expressed in cumulus cells, while AMHR2 is produced in both cumulus cells and oocytes. AMH had no significant effect on COCs nuclear maturation, whereas it inhibited the stimulatory effects of FSH on COCs maturation and cumulus expansion. Moreover, AMH treatment effectively inhibited the positive effect of FSH on the mRNA expressions of Hyaluronan synthase 2 (Has2), Pentraxin 3 (Ptx3), and TNF-alpha-induced protein 6 (Tnfaip 6) genes in COCs. In addition, AMH significantly decreased the FSH-stimulated progesterone production, but did not change estradiol levels. Taken together, our results suggest that AMH may inhibit the effects of FSH-induced COCs in vitro maturation and cumulus expansion. These findings increase our knowledge of the functional role of AMH in regulating folliculogenesis.