Chapter II the Melanin-Concentrating Hormone

Publisher Summary This chapter presents the most recent findings on structural analysis and neurobiology of melanin-concentrating hormone (MCH), with special emphasis on the cloning, functional characterization and neuronal distribution of at least two MCH receptors. It was a long-standing and important achievement. MCH is classified as a melanotropin—that is, a factor implicated in regulating color tegument. However, unlike the MSH and adrenocorticotropic hormone (ACTH) peptide family, all derived from the prepro-opio-melanocortin (POMC) precursor, MCH is not classified as a melanocortin because it lacks the consensus melanocortin sequence -His-Phe-Arg-Trp-. Consistent with that, MCH does not signal through the specific set of not less than six G-protein-coupled receptor (GPCR) proteins binding MSHs and ACTH, and termed from MC-1 to MC-6 binding. Intriguingly, it may be possible that MCH and MSH are evolutionary related.