In Vitro Release of Progesterone and Prostaglandins F and E by Porcine Luteal and Endometrial Tissue during Induced Luteolysis

Abstract

Prostaglandin F_2α (PGF_2α) has been proposed as the uterine luteolysin in the ewe (1) and pig (2). The corpus luteum (CL) of the pig may also participate in its own demise by means of increased luteal PGF synthesis during luteolysis (3). Both endometrial and luteal PGF synthesis in vitro were higher during the late luteal phase of the cycle than at any other stage of the cycle, but the temporal relationship between endometrial and luteal PGF release in vitro during luteolysis was not established (3). We have found that an increase in endometrial PGF synthesis in vitro starts after day 12 of the cycle, preceding any increase in luteal PGF synthesis in vitro by approximately two days (4).