Receptor for relaxin. The activity of this receptor is mediated by G proteins leading to stimulation of adenylate cyclase and an increase of cAMP. May also be a receptor for Leydig insulin-like peptide (INSL3). Expressed mainly in the brain, kidney, muscle, testis, thyroid, uterus, peripheral blood cells and bone marrow. The disease is caused by variants affecting the gene represented in this entry. Belongs to the G-protein coupled receptor 1 family. It is uncertain whether Met-1 or Met-18 is the initiator.