1996 Volume 58 Issue 2 Pages 141-144
Bovine follicular cysts were induced by treatments with ACTH (3 mg, im) daily for 14 days beginning in the late luteal phase. Cortisol concentrations in plasma significantly increased after ACTH treatments. During the formation of follicular cysts induced by the injections of ACTH, mean plasma concentrations of progesterone were significantly higher than those in the untreated preovulatory period, while mean plasma concentrations of estradiol-17β were significantly lower. During the treatment period, mean plasma concentrations of LH and FSH remained low, and the preovulatory surges of LH and FSH did not occur. Suppressed concentrations of LH and FSH might be caused by the increases in secretions of cortisol and progesterone, and by the decrease in secretion of estradiol-17β.