THE HUMAN PLACENTA AND FETAL MEMBRANES EXPRESS THE CORTICOTROPIN-RELEASING HORMONE-RECEPTOR 1-ALPHA (CRH-1-ALPHA) AND THE CRH-C VARIANT RECEPTOR

Placentally derived CRH plays a major role in the mechanisms controlli ng human pregnancy and parturition. It has been suggested that there i s a CRH placental clock that is active from the early stages of pregna ncy and determines the length of gestation and the timing of parturiti on. CRH can influence human reproductive tissue function via specific CRH receptors. Two distinct CRH receptors have been cloned (R1 and R2) that share 70% homology at the amino acid level and exist as two alte rnatively spliced forms (alpha and beta). In this study we investigate d the presence of CRH receptor subtypes in human fetal membranes deriv ed from spontaneous rupture and placental biopsies at term. Using RT-P CR, me identified the full length, of the CRH-R1 alpha subtype in plac ental and fetal membranes. In both tissues we also identified a splice d variant of the CRH receptor (CRH-Rc). We were unable to detect any C RH-R2 messenger ribonucleic acid in any of the biopsies. Fluorescent i n situ hybridization and immunofluorescence in both tissues demonstrat ed that syncytiotrophoblast cells and amniotic epithelium are the majo r cell types expressing CRH-1 alpha and CRH-Rc receptor messenger ribo nucleic acid. Further studies are necessary to give a better insight i nto the role of CRH and its receptors in these tissues.