Relaxin is a small peptidehormone comprising two subunits, together about 6,000 Da in size. Relaxin has been identified as a locally produced factor in a number of key tissues, such as the thyroid gland, gastrointestinal tract, heart, uterus, and lung. Relaxin is known to function in cells by activating a G-protein-coupled receptor on the cell surface called LGR7 or RXFP1 (relaxin family peptide 1). The main functions of relaxin are linked to uniquely mammalian traits such as lactation, viviparity, and post-reproductive survival.
Relaxin is a small peptidehormone belonging to the insulin family of hormones and growth factors. Its major sources in the body are in women the corpus luteum of the premenopausal ovary and the placenta and in men the prostate gland. In humans, unlike most other mammals, there are two genes for relaxin, RLN1 and RLN2. The products of these genes appear to behave identically in most bioassay systems. Since the RLN1gene product is...