This family consists of several mammalian pro-melanin-concentrating hormone (Pro-MCH) 1 and 2 proteins. Melanin-concentrating hormone (MCH) is a 19 amino acid cyclic peptide that was first isolated from the pituitary of teleost fish. It is produced from pro-MCH that encodes, in addition to MCH, NEI, and a putative peptide, NGE. In lower vertebrates, MCH acts to regulate skin colour by antagonising the melanin-dispersing actions of small alpha, Greek-melanocyte stimulating hormone (small alpha, Greek-MSH). In mammals, MCH serves as a neuropeptide and is found in many regions of the brain and especially the hypothalamus. It affects many types of behaviours such as appetite, sexual receptivity, aggression, and anxiety. MCH also stimulates the release of luteinising hormone.