[D-Trp8]-_-MSH is a selective melanocortin 3 (MC3) receptor agonist (IC50= 6.7, 340 and 600 nM for human MC3, MC5 and MC4 receptors respectively). It displays antiinflammatory
efficacy in mice bearing a non-functional MC1R (recessive yellow e/e
mouse) and these effects are abrogated in the presence of the HO-1 inhibitor ZnPPIX.