New Insights in Bovine Follicular Cysts

The aim of the present study was to understand the involved factors in follicular cysts in dairy cows. The study consisted of an in vivo and in vitro approach. The in vivo part, hormonal evaluation (Kisspeptin-10 [Kp-10], Gonadotropin inhibiting hormone [GnIH], Luteinizing hormone [LH], Oestrogens [E₂] and cortisol) was performed in sera of both healthy (H) and cows with follicular cysts (FC). The in vitro part was concentrated on estimating the distribution of GPR54 (Kp-10 receptor) and GPR147 (GnIH receptor) on cystic and preovulatory follicles. Serum concentrations of Kp-10, GnIH, LH, E₂ and cortisol were significantly higher in Group FC compared with Group H. Gene expression analysis showed a reduction in GPR54 mRNA levels in FC compared to preovulatory follicles, while no expression of the GPR147 receptor was detected. The lower presence of GPR54 in FC compared to the preovulatory follicle can be determined by a down-receptor regulation induced by elevated serum concentrations of Kp-10 in cows with ovarian FC. Endocrine imbalances of the hypothalamic-pituitary-ovarian axis, characterising FC, may reflect altered patterns of Kp-10 and GnIH secretion.