Altered Expression of Anti-Müllerian Hormone during the Early Stage of Bovine Persistent Ovarian Follicles.

Anti-Müllerian hormone (AMH) is a homodimeric glycoprotein expressed exclusively in the gonads. This hormone is an important regulator of the early growth of follicles through inhibitory effects on the recruitment of primordial follicles into the pool of growing follicles and on granulosa cell proliferation. Cystic ovarian disease (COD) is an important disorder affecting the fertility of dairy cattle. In the present study, we evaluated the expression of AMH in granulosa cells and AMH secretion into follicular fluid in pre-ovulatory follicles from control cows, animals with spontaneously arising COD and during the development of the disease, at 5, 10 and 15 days of follicular persistence. To this end, after an oestrous synchronization protocol, low doses of progesterone was administered for 5, 10 and 15 days after the expected day of ovulation (day 0 of follicular persistence) in treated cows (groups P5, P10 and P15, respectively), using an intravaginal progesterone-releasing device. Results showed a decrease in the expression of AMH in granulosa cells throughout folliculogenesis (P <0.05) and in the spontaneously arising follicular cysts and persistent follicles related to the control group (P <0.05). There was also a higher concentration of AMH in the follicular fluid of persistent follicles at 10 and 15 days of follicular persistence (P <0.05). Together, these results may indicate an alteration in AMH expression and secretion, which occurs early in folliculogenesis and incipiently during the development of COD, and which could contribute to the recurrence of this disease in cattle.