Melanocortin receptor 5 is located on the chromosome 18 in the human genome. when the melanocortin 5 receptor was disrupted in transgenic mice, it induced disruption of their exocrine glands and resulted in decreased production of sebum. Melanocortin-1 receptor (MC1R) is found in melanocytes and appears to be the alpha-melanocyte stimulating hormone (MSH) receptor. MC2R is localized to adrenocortical cells and is thus thought to be the ACTH receptor. MC3R and MC4R are localized primarily to sites in the brain. Each receptor has a unique pattern of affinity for the various melanocortin ligands. Gantz et al. (1994) reported the molecular cloning of a novel gene encoding a fifth member of the MCR family in the mouse. Chowdhary et al. (1995) mapped the human MC5R gene to 18p11.2 by fluorescence in situ hybridization.