RXFP2 (LGR8) is a receptor for relaxin. The activity of this receptor is mediated by G proteins leading to stimulation of adenylate cyclase and an increase of cAMP. It is also a receptor for Leydig insulin-like peptide (INSL3), and disruption in INSL3/RXFP2 signaling due to mutations in either gene results in intraabdominal cryptorchidism in mice. RXFP2 has been shown to be important for testis descent. In immunohistochemistry, RXFP2 has membranous positivity in the testes, brain, uterus, adipose tissue, thyroid, adrenal gland, reproductive tissues, smooth muscle, bone marrow, peripheral blood leukocytes, and skeletal muscle. It is also rpesent on neuroendocrine cells of the small intsestine and on macrophages. In the brain, RXFP2 is present on subsets of neurons in the medulla, with less intensive staining in the hippocampus and amygdala. References: Ann N Y Acad Sci. 2009 Apr;1160:197-204, PMID: 19416188