Peroxisome proliferator activated receptor ligands affect porcine endometrial steroids production during the estrous cycle and early pregnancy: an in vitro study

摘要

In the present study, we investigated the effect of PPAR ligands on progesterone (P-4) and 17 beta-estradiol (E-2) secretion, as well as 3 beta-hydroxysteroid dehydrogenase/Delta(5)-Delta(4) isomerase (3 beta-HSD) mRNA expression, in porcine endometrial slices collected on days 10-12 and 14-16 of the estrous cycle or early pregnancy. The explants were incubated in vitro for 6 h in the presence of PPAR alpha ligands - WY-14643 (agonist) and MK 886 (antagonist); PPAR beta ligands - L-165041 (agonist) and GW 9662 (antagonist); PPAR gamma ligands - 15d-prostaglandin J(2) and rosiglitazone (agonists) and T0070907 (antagonist). During the estrous cycle, all PPAR ligands inhibited P-4 secretion during the mid-luteal phase (days 10-12). During early pregnancy, a stimulatory effect of PPAR alpha agonist was observed during maternal recognition of pregnancy (days 10-12), while an inhibitory effect was observed at the beginning of implantation (days 14-16). PPAR ligands inhibited the expression of 3 beta-HSD mRNA on days 14-16 of the estrous cycle (beta and gamma isoforms) or pregnancy (alpha, beta, gamma isoforms) but did not affect gene expression on days 10-12 of the estrous cycle or early pregnancy. An inhibitory effect of PPAR alpha, PPAR beta, and PPAR gamma on E-2 secretion was observed during maternal recognition of pregnancy, but a stimulatory effect was observed during mid- (gamma isoform) or late-luteal (beta isoform) phases of the estrous cycle. Our study indicates, for the first time, that PPARs are engaged in P-4 and E-2 production in porcine endometrium. It is possible that the diverse receptivity of endometrial tissue to the PPAR ligands can be associated with the reproductive status of gilts.