Definition
A family of five G protein-coupled receptors (MC1R–MC5R) regulating pigmentation, energy balance and more.
Melanocortin receptors are five G protein-coupled receptors, MC1R to MC5R, activated by peptides derived from pro-opiomelanocortin, such as α-MSH and ACTH. MC1R regulates skin pigmentation, MC2R mediates ACTH action on the adrenal cortex, and MC3R and MC4R in the brain regulate energy balance and appetite. Synthetic melanocortin peptides differ in receptor selectivity. Afamelanotide (Melanotan I) is an approved prescription medicine for erythropoietic protoporphyria, bremelanotide (PT-141) for hypoactive sexual desire disorder in premenopausal women, and setmelanotide for obesity caused by specific genetic defects in the MC4R pathway. Melanotan II is non-selective and not approved.