α-Melanocyte-stimulating hormone (α-MSH) is a 13-amino acid peptide hormone produced by post-translational processing of proopiomelanocortin (POMC) in the pituitary gland, as well as in keratinocytes, astrocytes, monocytes, and gastrointestinal cells.1 It is an agonist of melanocortin receptor 3 (MC3R) and MC4R that induces cAMP production in Hepa cells expressing the human receptors (EC50s = 0.16 and 56 nM, respectively).2 α-MSH (100 pM) reduces S. aureus colony formation and C. albicans germ tube formation in vitro.3 It inhibits endotoxin-, ceramide-, TNF-α-, or okadaic acid-induced activation of NF-κB in U937 cells.1 α-MSH reduces IL-6- or TNF-α-induced ear edema in mice.4 It also prevents the development of adjuvant-induced arthritis in rats and increases survival in a mouse model of septic shock. Increased plasma levels of α-MSH are positively correlated with delayed disease progression and reduced death in patients with HIV.1
1.Catania, A., Airaghi, L., Colombo, G., et al.α-melanocyte-stimulating hormone in normal human physiology and disease statesTrends Endocrinol. Metab.11(8)304-308(2000) 2.Miwa, H., Gantz, I., Konda, Y., et al.Structural determinants of the melanocortin peptides required for activation of melanocortin-3 and melanocortin-4 receptorsJ. Pharmacol. Exp. Ther.273(1)367-372(1995) 3.Cutuli, M., Cristiani, S., Lipton, J.M., et al.Antimicrobial effects of a-MSH peptidesJ. Leukoc. Biol.67(2)233-239(2000) 4.Lipton, J.M., Ceriani, G., Macaluso, A., et al.Antiiinflammatory effect of the neuropeptide a-MSH in acute, chronic, and systemic inflammationAnn. N.Y. Acad. Sci.25(741)137-148(1994)