Abstract
Summary
Administration of prostaglandin F2α (PGF2α) or luteinizing hormone (LH) induces luteolysis in the rabbit. The present study was designed to compare the effect of estrogen treatment on the luteolytic action of PGF2α and LH in pseudopregnant Dutch Belted rabbits. PGF2α (500 μg administered subcutaneously twice a day on days 9 through 12 of pseudopregnancy) reduced (p < .001) corpora lutea weights by day 14 and lowered peripheral plasma progestin levels on days 11 (p < .001) and 14 (p < .05). LH (50 μg intravenously on day 9) comparably reduced corpora lutea weights although plasma progestin levels increased due to LH-induced ovulations. In animals receiving 17β-estradiol (20 μg/day subcutaneously on days 9 through 12) plus LH, corpora lutea weights did not differ significantly from controls. Corpora lutea in rabbits receiving 17β-estradiol plus PGF2α were heavier (p < .05) than in animals receiving PGF2α alone but less (p < .05) than controls. This luteo-tropic effect of estradiol was also reflected by the presence of significant (p < .05) plasma progestin concentrations on days 11 and 14. A 5-fold increase in the dose of PGF2α did not completely overcome the luteotropic effect of 17β-estradiol.
Get full access to this article
View all access options for this article.