Melanocortin Axis
The melanocortin axis comprises five G-protein-coupled receptors (MC1R-MC5R) activated by alpha-MSH and ACTH-derived ligands. MC4R drives appetite, energy expenditure, and sexual function via central hypothalamic neurons. PT-141 (bremelanotide) is the FDA-approved MC4R agonist (Vyleesi, 2019). MC1R drives melanocyte pigmentation. KPV (Lys-Pro-Val), the C-terminal alpha-MSH tripeptide, retains anti-inflammatory activity without melanogenic activity.
