Expression Patterns of CRH, CRH Receptors, and CRH Binding Protein in Human Gestational Tissue at Term

Recent research suggests a significant role for placental corticotropin-releasing hormone (CRH) in controlling human parturition. This paper describes the expression of CRH, CRH receptors 1 and 2, and CRH binding protein (CRH-BP) in gestational tissue in late pregnancy. Placenta, myometrium, decidua, and fetal membranes were collected after uncomplicated pregnancies at term caesarian section before the onset of labour. The localisation and mRNA expression of CRH, CRH receptors, and CRH-BP were studied by immunohistochemistry and reverse transcription (RT)-PCR. CRH receptors were detected in placenta, myometrium, decidua, and fetal membranes. We demonstrated for the first time the presence of CRH receptors on resident macrophages and on endothelial cells. CRH receptor 1 mRNA was detected in all tissues investigated by RT-PCR, whereas CRH receptor 2 mRNA was restricted to myometrium and decidua. CRH mRNA was widely expressed in all tissue under study. Novel findings are also presented on the expression of CRH-BP in the myometrium. This widespread expression of the CRH system in gestational tissue suggests a paracrine role for CRH in the birth process (e.g. effects on macrophages and endothelial cells).