Regulation of the oxytocin receptor in bovine reproductive tissues and the role of steroids

Abstract

The oxytocin receptor (OTR) plays a central role in the functioning of the reproductive tract in the female ruminant. During the oestrous cycle endometrial OTR is suppressed through most of the cycle, probably in a progesterone-dependent manner, to be massively up-regulated during the few days before and after oestrus. At this time, luteal OT triggers a positive feedback loop, the endometrial OTR mediating the release of luteolytic PGF(2α) which feeds back to the corpus luteum to cause the secretion of more OT and to induce luteolysis. This feedback is only interrupted if a newly formed blastocyst is present. Ruminant blastocysts secrete the cytokine interferon-τ, which interacts directly wi..