grantor:
University of TorontoThe human placenta secretes increasing concentrations of corticotropin-releasing hormone (CRH) in late pregnancy and in labour. CRH has been implicated in the regulation of myometrial contractility. We hypothesized that CRH receptors, CRH-R1 and CRH-R2, mRNA in the myometrium would be upregulated in labour. Myometrial samples were collected from nonpregnant, pregnant and laboring patients from the upper and lower uterine segment. CRH-R1 mRNA and protein were downregulated with pregnancy and significantly upregulated at labour. This rise appeared to be exclusive to the lower segment. CRH-R2 mRNA did not change. Rats have been used extensively to study the regulation of CRH receptors. We examined CRH receptor mRNA in rat myometrium. CRH-R1 mRNA was undetectable. CRH-R2 mRNA was significantly increased at labour concomitant with a rise in connexin 4; mRNA, a gap junction protein associated with labour. In conclusion, at the time of labour CRH-R1 mRNA is upregulated in the human but in the rat CRH-R2 mRNA is upregulated.M.Sc
