Effect of local or parenteral application of ACTH or hydrocortisone on bovine corpus luteum function

Studies were conducted to determine the effect on corpus luteum (CL) function of ACTH or hydrocortisone administered by ovarian perfusion on day 11 of the oestrous cycle or by carotid infusion on days 2-9 of the oestrous cycle. No significant local effects on CL function were observed during the ovarian perfusion study. Continuous carotid infusion of ACTH or hydrocortisone on days 2-9 resulted in a decreased slope of the progesterone increase during the infusion period. However, no difference in plasma progesterone level on days 9-11 between control and treated cycles was detected and there was no difference between treated and control CL at day 11 with regard to CL weight or progesterone content. The data suggest a possible direct effect of hydrocortisone on either the hypothalamus or pituitary which results in decreased progesterone secretion but not CL development. No residual effect was observed.