ACTH Induces Differential Changes in Steroidal Hormone Secretion in the Wall of Bovine Antral and Cystic Follicles.

HUGO H ORTEGA; AYELEN AMWEG; ALFONSO PAREDES; NATALIA SALVETTI; HERNAN E. LARA

Pittsburgh, Pennsylvania

Congreso; 42nd Annual Meeting, Society for the Study of Reproduction (SSR); 2009

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Cystic ovarian disease (COD) is one of the most common causes of reproductive failure in cattle, and the mechanisms that lead to the development of follicular cysts have been the object of speculation and research for many years, but  they are still little understood. It is believed that COD has a multifactorial etiology, and has been reported that follicular cysts are caused by an endocrine imbalance in the hypothalamo-hypophyseal-gonadal axis, with possible participation of stress as an important factor incorporating to the adrenal gland in this axis. We have previously demonstrated a participation of sympathetic nervous system in the effect of stress in ovarian cyst formation but we cannot discard a simultaneous participation of adrenocorticotropic hormone (ACTH) as has been demonstrated to be an important stress response factor. In this work we tested if ACTH can also affect follicular components altering the normal steroid secretion directly, as a mechanism that could be present in follicular cyst.  To test this hypothesis, fragments of ovarian follicular wall of large antral and spontaneous cystic follicles were cultured in serum free medium for a 20min, after which tissues were placed in medium with ACTH (1x10-9M, 1x10-8M and 1x10-7M). Previously, the levels of steroid (estradiol, progesterone, testosterone and cortisol) in follicular fluid were analyzed by enzyme immunoassay. After three hours of incubation, the culture medium was separated and the steroid hormones were analyzed and compared with basals levels without ACTH stimulation. In all cases, basal levels of steroids secretion were detected. In the analysis of culture medium of large antral follicles steroid levels, a significantly dose-dependent increase in testosterone was observed. Also, in cystic follicles, higher values of cortisol, testosterone and estradiol were observed in response to ACTH stimulation. A differential response of cysts in relation to large antral follicles was observed in the secretion of cortisol and estradiol. Our results indicate that ACTH may affect the steroid secretion in bovine ovarian follicles and that follicular cysts have a differential response, unlike that of healthy follicles. These findings support the notion that stress affects the ovarian function and that ACTH could be one of the factors that participate in the etiology of COD in bovines. (Supported by APCyT grants PICT-2007-01193  BID 1728 OC/AR).