Indomethacin treatment prevents prolactin-induced luteolysis in the rat

Abstract

Adult female rats were hypophysectomized and their pituitary glands autotransplanted beneath the left kidney capsule on day 2 (day 1 was the day of ovulation). In such rats the pituitary secretes prolactin fairly constantly and the corpora lutea secrete progesterone for several months. To induce the luteolytic effect of prolactin the rats were first injected s.c. with 2-bromo-alpha-ergocryptine (CB-154) on cycle days 12, 13 and 14 (i.e. 10, 11 and 12 days after operation) to depress prolactin secretion, and then with CB-154 vehicle (70% ethanol) daily until cycle day 21, to allow prolactin secretion to resume. One ovary was removed from each rat on day 15 and the remaining one on day 22. The mean (+/- S.E.M.) weight of the corpora lutea on day 15 was 1.46 +/- 0.06 mg and 0.98 +/- 0.07 mg on day 22 (n = 17). In contrast, rats in which the CB-154 treatment was maintained to day 21 had corpora lutea which weighed 1.31 +/- 0.09 on day 15 and 1.47 +/- 0.08 mg on day 22 (n = 15). To investigate whether indomethacin, a prostaglandin synthesis inhibitor, affected the luteolytic action of prolactin, the experiment was repeated, but on day 15 (after the removal of one ovary) the groups in which CB-154 treatment was stopped, as well as the group in which CB-154 treatment was maintained, were each divided into two groups. In one, indomethacin-containing silicone elastomer wafers and, in the other, blank silicone elastomer wafers, were placed within the bursa of the remaining ovary.(ABSTRACT TRUNCATED AT 250 WORDS)