Direct effects of oestradiol-17β and prostaglandin E-2 in protecting pig corpora lutea from a luteolytic dose of prostaglandin F-2α

Abstract

Implants containing vehicle or oestradiol-17β (10 mg) were placed into pairs of corpora lutea (CL) with and without prostaglandin F-2α (PGF-2α)(100 μg) on Day 11 and CL were collected on Day 19, in cyclic gilts (Exp. 1). The results demonstrated that CL implanted with PGF-2α with or without oestradiol-17β had a markedly lower (P< 0.01) weight (mg) and progesterone concentration (ng/mg) than CL with vehicleor oestradiol-17β-implanted or unimplanted CL, which were similar (149 and 7.2 vs. 304 and 49.6, respectively) . In Exp. 2, CL implanted with vehicle, oestradiol-17β or PGE-2 remained fully functional until Day 19, whereas CL implanted with oestradiol-17β ± PGF-2α and PGE-2 + PGF-2α exhibited lower (P< 0.05) weight and progesterone concentrations; CL implanted with PGE-2 + PGF-2α were heavier (P< 0.05) and tended (P< 0.10) to have greater progesterone concentrations than CL implanted with oestradiol-17β + PGF-2α. In Exp. 3, a dose-dependent (P< 0.05) effect of PGE-2 on preventing regression induced by PGF-2α was observed on Day 19. These data demonstrate a direct effect of PGE-2, but not of oestradiol-17β in protecting the CL against luteolysis induced by PGF-2α.