Altered ovarian follicle function in ACTH-treated gilts

To assess the possible influence of increased endogenous glucocorticoid levels on ovarian function, gilts were treated with either adrenocorticotrophic hormone (ACTH) or saline during the luteal phase of the oestrous cycle, from day 9 to day 14, and ovariectomised on day 14. Individual follicles were dissected from each ovary and their follicular fluid (FF), granulosa and theca cells were recovered. Cell viability was determined by dye exclusion. Cortisol (C), oestradiol-17β (E2), oestrone (E1), testosterone (T) and androstenedione (A) concentrations were measured in FF while cellular oestrogen and androgen production was assessed during a 3 h incubation period. eroid hormone profile in FF was significantly altered in the treatment group. Follicles collected from ACTH-treated gilts were characterised by elevated C (P < 0.001), and E1 (P < 0.05), but lower T and A (P < 0.01) levels; E2 values also tended to be lower, but not significantly so. An increase (P < 0.01) in the proportion of follicles with lower granulosa cell viability was observed on the ovaries of ACTH-treated gilts. There were no significant differences in E2 or E1 production, based on viable cell numbers, during the 3 h incubation by either granulosa or theca cells from control and ACTH-treated gilts. Theca cells collected from treated animals, however, produced significantly lower (P < 0.01) A concentrations. These results indicate that ACTH treatment leading to elevated endogenous glucocorticoid levels during the luteal phase of the oestrous cycle, prior to follicle recruitment, can reduce the proportion of viable granulosa cells per follicle. This change is associated with altered steroid hormone concentrations in FF, but does not appear to involve suppression of aromatase activity.