The MC2R gene provides instructions for making a protein called adrenocorticotropic hormone (ACTH) receptor. This protein is found primarily in the adrenal glands, which are hormone-producing glands located on top of each kidney.~The ACTH receptor is embedded in the membrane of cells where it attaches (binds) to ACTH. ACTH is a hormone that is released by the pituitary gland, located at the base of the brain. The binding of ACTH to its receptor triggers the adrenal glands to produce a group of hormones called glucocorticoids. These hormones, which include cortisol and corticosterone, aid in immune system function, play a role in maintaining normal blood sugar (glucose) levels, help trigger nerve cell signaling in the brain, and serve many other purposes in the body.~The ACTH receptor also likely plays a role in the development of the adrenal glands before birth.