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

DANIELA PEREZ-SIRKIN; MAXIMILIANO CÁNEPA; MARIANA FOSSATI; JUAN I. FERNANDINO; TOMAS H. DELGADIN; LUIS F. CANOSA; GUSTAVO M. SOMOZA; PAULA VISSIO

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 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 for the first time the sequence of MCH and GH cDNA in Cichlasoma dimerus, a freshwater South American cichlid fish. Besides, we tested if MCH can regulate GH synthesis and/or release in this species. We also detected, by double label confocal immunofluorescence, contacts between MCH fibers and GH cells in the proximal pars distalis indicating a possible functional relationship. MCH increased GH transcript levels and stimulated GH release in pituitary cultures. C. dimerus exposed to a white background presented a greater number of MCH cell bodies with a larger nuclear area and higher levels of MCH transcript than fish exposed to a black background. Besides, fish reared in white background showed a greater body weight and total length compared to those from black background, suggesting that MCH is maybe related to somatic growth. Our results report for the first time in fish, that MCH is involved in the regulation of the synthesis and release of GH and probably in fish growth rate.