title: Progesterone secretion and prostaglandin F release in vitro by endometrial and luteal tissue of cyclic pigs.
abstract: Blood and tissue were collected from 30 pigs on various days of the oestrous cycle to compare progesterone in peripheral plasma and progesterone release in vitro with prostaglandin (PG) F release in vitro by endometrial and luteal tissue (approximately 100 mg in 5 ml Krebs-Ringer-bicarbonate buffer, pH 7.4, for 2 h with three different incubation treatments). Plasma progesterone increased from Days 8 to 12 of the oestrous cycle (25.1 to 42.8 ng/ml, P < 0.05) and decreased from Day 14 to 16 (36.3 to 5.9 ng/ml, P < 0.05). Progesterone release in vitro at 37 degrees C decreased from 18.0 to 2.7 ng/mg tissue from Days 8 to 16 (P < 0.05). Endometrial PGF release in vitro at 37 degrees C increased slightly from Day 8 to 14, then increased significantly from 43.7 to 103.5 ng/100 mg tissue between Days 14 and 16 (P < 0.05). The rapid increase in endometrial PGF release coincided with the decrease in plasma progesterone. A small, non-significant increase in mean luteal PGF release was detected between Days 14 and 16. The results of this experiment did not suggest a critical role for luteal PGF-2 alpha in the process of luteolysis in the pig, but do provide indirect evidence for the involvement of endometrial PGF-2 alpha in luteolysis in the pig.
mesh_terms: D000818:Animals; D003338:Corpus Luteum / Q000378:metabolism*; D004717:Endometrium / Q000378:metabolism*; D004971:Estrus; D005260:Female; D066298:In Vitro Techniques; D011247:Pregnancy; D011374:Progesterone / Q000097:blood / Q000378:metabolism*; D011460:Prostaglandins F / Q000378:metabolism*; D013552:Swine / Q000502:physiology*
chemical_list: D011460:Prostaglandins F; D011374:Progesterone