Abstract
The objective of the present study was to determine whether corticotropin-releasing hormone (CRH) influences porcine corpus luteum function. The gene expressions of CRH receptors (CRH-R) were determined in the CL of Chinese Meishan pigs during the estrous cycle. The effects of CRH on progesterone (P), estradiol-17β (E) and prostaglandin (PG) F2α secretion by cultured luteal cells were also investigated. Messenger RNAs of the CRH-R were clearly expressed in the CL throughout the estrous cycle, and the mRNA level was higher at the regressed stage than at the other stages (P<0.05). When the cultured luteal cells obtained from mid-luteal stage CL (days 8–11) were exposed to CRH (50–5,000 ng/ml), P secretion by the cells were significantly reduced at the highest dose (P<0.05), whereas CRH had no effect on E and PGF2α secretion by the cells. The overall results suggest that CRH inhibits locally P production from the luteal cells via its specific CRH-R, implying CRH plays some roles in regulating porcine CL function during the estrous cycle, especially at the period of luteolysis.
