The melanin-concentrating hormone (MCH) is a cyclic neuropeptide isolated initially from salmon pituitary gland and later from rat hypothalamus. In mammals, MCH perikarya are confined largely to the lateral hypothalamus and zona incerta area with extensive neuronal projections throughout the brain, including the neurohypophysis. The anatomic distribution suggests a neurotransmitter or neuromodulator role for MCH in a broad array of neuronal functions directed toward the regulation of goal-directed behavior, such as food intake, and general arousal. MCH and 2 other putative neuropeptides, NEI and NGE, are encoded by the same precursor and appear colocalized in nerve cells and in many instances within the projections. The precursor is designated pro-melanin-concentrating hormone (PMCH) (summary by Nahon et al., 1992 [PubMed 1572663]).[supplied by OMIM, Jan 2011]