Relaxin Receptor Antibodies

The relaxin receptor family consists of four G protein–coupled receptors—RXFP1, RXFP2, RXFP3, and RXFP4—which bind distinct members of the relaxin/insulin-like peptide family and mediate diverse physiological functions. RXFP1 primarily binds relaxin-2 and signals through Gs and Gi/o proteins to elevate cAMP and activate NO and MAPK pathways, contributing to reproductive tissue remodeling, cardiovascular regulation, and antifibrotic effects. RXFP2, which binds INSL3, also couples to Gs proteins and plays a critical role in testicular descent and reproductive function. In contrast, RXFP3 and RXFP4 preferentially couple to Gi/o proteins, leading to inhibition of adenylate cyclase and modulation of neuronal and metabolic signaling. RXFP3, the receptor for relaxin-3, is mainly expressed in the brain and regulates stress, feeding, arousal, and cognition, while RXFP4, the receptor for INSL5, is expressed in the gut and hypothalamus and influences appetite and energy balance. Collectively, the relaxin receptor family integrates endocrine, neural, and metabolic pathways, coordinating processes from reproduction and tissue remodeling to energy homeostasis and stress responses. Because of their broad physiological impact, these receptors are considered promising therapeutic targets for conditions including fibrosis, heart failure, infertility, obesity, and mood disorders. For more information on relaxin receptor pharmacology please refer to IUPHAR database.