Binding sites for melanin-concentrating hormone in the human brain

Binding sites for melanin-concentrating hormone (MCH) in human brain were i nvestigated and characterized by radioligand binding Specific binding sites for MCH were present in every region of human brain (cerebral cortex, cere bellum, thalamus, hypothalamus, pens, and medulla oblongata) obtained at au topsy. alpha-Melanocyte stimulating hormone or ACTH was a Door inhibitor of I-125-MCH binding (IC50 > 1 mu M) compared with MCH (IC50 = 0.3 +/- 0.07 n M, mean +/- SEM, n = 3). Scatchard plots of I-125-MCH binding in human brai n (thalamus) gave a dissociation constant of 0.2 +/- 0.06 nM and maximal bi nding of 5.8 +/- 0.3 fmol/mg protein (n = 3). These findings suggest that s pecific MCH binding sites that differ from the melanocortin receptors exist in human brain. (C) 2000 Elsevier Science Inc. All rights reserved.