Sheep with ovarian androgen excess have fibrosis and follicular arrest with increased mRNA abundance for steroidogenic enzymes and gonadotropin receptors

Abstract An androgen excess ovarian micro-environment may limit follicle progression in sheep. Two populations of ewes with divergent follicular fluid androstenedione (A4) were identified in a flock in Jordan: High A4; (A4) ≥ 30 ng/mL, (N = 12) or Control A4 (Control); A4 ≤ 15 ng/mL; (N = 12). We hypothesized High A4 ewes would have increased steroidogenic enzyme mRNA abundance, inflammation, and follicular arrest. Messenger RNA abundance for steroidogenic enzymes StAR, CYP17A1, CYP11A1, and HSD3B1 were increased in theca cells while CYP17A1, CYP19A1, and HSD3B1 were increased in granulosa cells in High A4 ewes compared to Control. Gonadotropin receptor mRNA expression for LHCGR was increased in theca and FSHR in granulosa in High A4 ewes. Messenger RNA expression of FOS when reduced, increases expression of CYP17A1 which was observed in High A4 granulosa cells compared to Control. Furthermore, High A4 ewes had greater numbers of primordial follicles (P