Autoradiographic Analysis of the Relaxin Receptor in Human Fetal Membranes

Abstract

Relaxin is a polypeptide hormone best known for its role in pregnancy and parturition, it is synthesized as a single chain polypeptide precursor composed of a B chain, C peptide, and A chain. The C peptide is proteolytically cleaved from this precursor during processing to form the mature molecule. Presently two genes that code for human relaxin have been identified, and they are termed H1 and H2. The nucleotide sequence of the first human relaxin gene was obtained by using a porcine relaxin cDNA probe to screen a human genomic library and was called H1 (1). However, early studies failed to show relaxin H1 gene expression in tissues known to be sources of relaxin. These results suggested the presence of another human relaxin gene. Using a probe derived from the relaxin H1 to screen a cDNA library made from RNA isolated from the human corpus luteum of pregnancy, a second human relaxin gene was identified termed H2 (2). Subsequently, both genes were mapped on chromosome 9 (3).