Binding and cAMP Studies of Melanotropin Peptides with the Cloned Human Peripheral Melanocortin Receptor, hMC1R

Abstract

Binding and stimulation of cAMP by the melanotropin peptides [alpha]-MSH ([alpha]-melanocyte-stimulating hormone) and its superpotent analogues [Nle4, Phe7] [alpha]-MSH (MT-I) and [formula] [alpha]-MSH4-10-NH2 (MT-II) were undertaken to examine their respective properties on the human peripheral melanocyte melanocortin receptor, hMC1R. [alpha]-MSH was found to possess a binding IC50 value of 6.5 +/- 0.9 x 10-9 M and cAMP EC50 value of 2.0 +/- 0.6 x 10-9 M. MT-I possesses a binding IC50 value of 1.2 +/- 0.3 x 10-9 M and a cAMP EC50 of 0.5 +/- 0.03 x 10-9 M. MT-II possesses a binding IC50 of 0.57 +/- 0.08 x 10-9 M and cAMP EC50 value of 0.20 +/- 0.05 x 10-9 M.