Insulin-like peptide 5 (INSL5)

Insulin-like peptide 5 (INSL5) is a 45-amino acid peptide hormone of the relaxin/insulin family, characterized by two peptide chains (A and B) cross-linked by three disulfide bonds, similar to insulin. It is secreted mainly by colonic L-cells and acts through the relaxin family peptide receptor 4 (RXFP4), which is a G protein-coupled receptor. INSL5 has been shown to regulate insulin secretion, appetite, and colonic motility, and RXFP4 is being investigated as a potential therapeutic target for treatment of metabolic diseases (such as obesity, diabetes, and anorexia) and gastrointestinal motility disorders (including constipation and diarrhea). No approved drugs target INSL5 in current clinical use, but synthetic analogs and RXFP4 agonists are under active research.

Other names

INSL5insulin-like peptide 5relaxin family peptide 5

Peptide agonists (including native INSL5 and designed analogs) bind to and activate RXFP4, a G protein-coupled receptor, triggering intracellular cAMP signaling and downstream physiological effects (including modulation of motility and appetite)