Characterization of melanin-concentrating hormone in chum salmon pituitaries

Abstract

Many lower vertebrates exhibit colour change in response to the background. A dual hormonal control of colour change by two antagonistic pituitary melanophorotropic hormones was first postulated in amphibia by Hogben and Slome. It is well established that the melanotropins alpha- and beta-MSH are responsible for pigment dispersion in the integumentary melanophore of lower vertebrates and that these molecules are derived from a common precursor protein, proopiocortin, by specific processing within the intermediate lobe. No evidence has been found for an antagonistic hormone in amphibia, although the existence of such a molecule in the pituitary gland of teleost fishes has long been recognized and was termed the melanophore-concentrating hormone by Enami. Early attempts to separate the two hormones proved unsuccessful. Recently, Baker and Ball re-invoked the dual hormone concept, and it has been suggested that a melanin-concentrating hormone (MCH) is synthesized in the hypothalamus of teleosts and stored and released by the neurohyphophysis. We have now isolated a novel peptide from the pituitary of the salmon (Oncorhynchus keta) possessing an antagonistic function to MSH, and we describe here its chemical and biological characteristics.

MCH-containing neurons in the hypothalamus of the cat: Searching for a role in the control of sleep and wakefulness

“…The melanin-concentrating hormone (MCH) was initially characterized as a circulating factor mediating color change in teleost fish (Kawauchi, et al, 1983). Thereafter, MCH was identified in the rat and was found to be fully conserved in all mammals analyzed so far, including humans (Forray, 2003, Shi, 2004.…”

Genetics, development and evolution of adaptive pigmentation in vertebrates

“…Given the similarities in the genetic and developmental mechanisms of pheomelanin production in birds and mammals (Boswell and Takeuchi, 2005), it seems unlikely that they have evolved independently, although this question warrants further investigation. Further, reptiles, amphibians and teleost fish can regulate body color by aggregation or concentration of melanin granules in melanocytes (also referred to as melanophores) via a mechanism controlled by the melaninconcentrating hormone (Kawauchi et al, 1983;Nery and Castrucci, 1997).…”

Microinjections of melanin concentrating hormone into the nucleus tractus solitarius of the rat elicit depressor and bradycardic responses

“…In teleost fish MCH has been reported to regulate skin color (Kawauchi et al, 1983) while in mammals this peptide has been implicated in regulating feeding behavior and energy homeostasis; MCH increases food intake and decreases energy expenditure. For example, transgenic mice over-expressing MCH exhibit hyperphagia (Ludwig et al, 2001) and mice with genetic deletion of MCH are hypophagic, lean and have an increased rate of energy expenditure (Kokkotou et al, 2005;Shimada et al, 1998).…”

“…Melanin concentrating hormone (MCH) was initially isolated from salmon pituitaries (Kawauchi et al, 1983). Subsequently, an antiserum against salmon MCH was used for demonstrating the presence of MCH (Skofitsch et al, 1985;Zamir et al, 1986b) and for isolation and purification of this peptide from the rat hypothalamus (Vaughan et al, 1989).…”