Melanocortin-2 receptor (MC2R), also known as ACTH receptor (ACTHR), is a member of the melanocortin receptor family, consisting of five closely related genes that encode seven-transmembrane G protein-coupled receptors. Melanocortins (melanocyte-stimulating hormones and adrenocorticotropic hormone) are peptides derived from pro-opiomelanocortin (POMC). MC2R is selectively activated by adrenocorticotropic hormone (ACTH), whereas the other four melanocortin receptors recognize a variety of melanocortin ligands. In the adrenal cortex, ACTH interacts with the ACTH receptor (ACTH-R) to induce synthesis and secretion of glucocorticoids which involved in a wide variety of physiological processes such as carbohydrate metabolism and immune function.