ACTH, α-MSH, and control of cortisol release: cloning, sequencing, and functional expression of the melanocortin-2 and melanocortin-5 receptor in Cyprinus carpio

• DOI: 10.1152/ajpregu.00826.2004
• Publication Date: 2005-05-13T00:25:59Z
• Authors: Juriaan R. Metz; Edwin J. W. Geven; Erwin H. van den ...; Gert Flik
• Keywords: ACTH receptor; Melanocortin 3 receptor

Cortisol release from fish head kidney during the acute phase of stress response is controlled by adrenocorticotropic hormone (ACTH) pituitary pars distalis (PD). Alpha-melanocyte-stimulating (α-MSH) and β-endorphin, intermedia (PI), have been implicated in cortisol chronic phase. The present study addresses regulation ACTH α-MSH common carp ( Cyprinus carpio) includes characterization their receptors, namely, melanocortin-2 melanocortin-5 receptors (MC2R MC5R). We could not demonstrate corticotropic activity α-MSH, combinations these. do show a corticotrope PI, but its identity as yet uncertain. Carp restrained for 1 7 days showed elevated plasma levels; still lower at day than restraint. Interrenal capacity unaffected, estimated stimulation with maximum dose superfusion setup. MC2R MC5R appear phylogenetically well conserved. predominantly expressed kidney; low abundance was found spleen kidney. brain, PD, kidney, skin. Quantitative PCR analysis expression reveals mRNA downregulation after restraint, line levels seen. discuss corticosteroid production phylogenetic perspective. propose that increased exert positive feedback on hypothalamic corticotropin-releasing to sustain mild axis activity.