Two important systems in energy homeostasis: melanocortins and melanin-concentrating hormone

Our understanding of the regulation of appetite and energy balance has adva nced significantly over the past decade as several peptides, centrally or p eripherally expressed, have been characterized and shown to profoundly infl uence food intake and energy expenditure.(1) The growing number of putative appetite-regulating neuropeptides includes peptides that are orexigenic (a ppetite-stimulating) signals and anorectic peptides. Neuropeptide Y (NPY), melanin concentrating hormone (MCH), orexins A and B, galanin, and agouti-r elated peptide (AgRP) all act to stimulate feeding while alpha-melanocyte s timulating hormone (alpha MSH), corticotropin releasing hormone (CRH), chol ecystokinin (CCK), cocaine and amphetamine regulated transcript (CART), neu rotensin, glucagon-like peptide 1 (GLP 1), and bombesin have anorectic acti ons.(1) Leptin, expressed in the periphery in white adipose tissue, acts in the CNS to modulate the expression of several of these hypothalamic peptid es.(1) This creates a functional link between the adipose tissue and the br ain that translates the information on body fat provided by leptin to input into energy balance regulating processes. In the current review we examine the significant role of the melanocortin s ystem (alpha MSH, agouti and AgRP peptides, and their receptors and mahogan y protein) and melanin concentrating hormone in the regulation of energy ba lance. (C) 1999 Harcourt Publishers Ltd.