MCH may act as a neurotransmitter or neuromodulator in a broad array of neuronal functions directed toward the regulation of goal-directed behavior, such as food intake, and general arousal. May also have a role in spermatocyte differentiation. Predominantly expressed in lateral hypothalamus, also detected in pallidum, neocortex and cerebellum. Also found in thymus, brown adipose tissue, duodenum and testis (spermatogonia, early spermatocytes and Sertoli cells). No expression in peripheral blood. In brain exclusively mature MCH and NEI peptides are present. In peripheral tissues a large product, encompassing the NEI and MCH domains of the precursor, is found predominantly. Differentially processed in the brain and in peripheral organs producing two neuropeptides; NEI and MCH. A third peptide, NGE, may also be produced. Preferential processing in neurons by prohormone convertase 2 (PC2) generates NEI. MCH is generated in neurons of the lateral hypothalmic area by several prohormone convertases including PC1/3, PC2 and PC5/6. Belongs to the melanin-concentrating hormone family.