Melanin Concentrating Hormone (MCH) is involved in the regulation of growth hormone in Cichlasoma dimerus (Cichlidae, Teleostei).

PEREZ SIRKIN, D.I.; CÁNEPA, M.M.; FOSSATI M.; FERNANDINO, J.I.; DELGADIN, T.H.; CANOSA, L.F.; SOMOZA, G.M.; VIZZIO, P.G.

GENERAL AND COMPARATIVE ENDOCRINOLOGY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2012 vol. 176 p. 102 - 111

0016-6480

Growth hormone (GH) is the main pituitary hormone involved in somatic growth. In fish the neuroendocrine control of GH is multifactorial due to the interaction of multiple inhibitors and stimulators. Melanin-concentrating hormone (MCH) is a cyclic amino acid peptide, involved in skin color regulation. In addition, MCH has been related to the regulation of food intake in both mammals and fish. In mammals, there is only one report presenting evidences on the in vitro GH stimulation by MCH, but there are no data on non-mammals. In the present work, we report the molecular characterization of MCH and GH in Cichlasoma dimerus, a freshwater South American cichlid. Then, we tested if MCH can regulate GH synthesis and/or release affecting the growth rate of C. dimerus. Our results show that C. dimerus exposed to a white background grew faster, presented a greater number of MCH cells bodies with a greater nuclear area and higher levels of MCH transcript than fish exposed to a black background. By double label confocal immunofluorescence, we detected contacts between MCH fibers and GH cells in the proximal pars distalis indicating a possible functional relationship. Also MCH increased GH transcript levels and stimulated GH release in pituitary cultures. Our results suggest, for the first time in fish, that MCH is involved in the regulation of synthesis and release of GH and hence in growth rate.