Research Peptide · For laboratory research use only
Also known as Melanotan I
MT-1 (melanotan I, INN afamelanotide) is [Nle4, D-Phe7]-alpha-MSH, also abbreviated NDP-MSH: a linear 13-residue analogue of alpha-melanocyte-stimulating hormone in which methionine 4 is replaced by norleucine and phenylalanine 7 by its D-isomer1. It was described in 19801.
Early research used pigment cell bioassays in frog and lizard skin and mouse melanoma cells1,2, followed by toxicology studies in mice3. A review by the originating group traces the development of melanotan I and the related cyclic analogue melanotan II4. Afamelanotide has also been the subject of registered clinical trials5.
As described in the research literature
As described in the research literature, [Nle4, D-Phe7]-alpha-MSH was resistant to degradation by serum enzymes and showed markedly increased activity relative to alpha-MSH in the frog skin bioassay, mouse melanoma adenylate cyclase activation and melanoma cell tyrosinase stimulation; it was 26 times as potent as alpha-MSH in the adenylate cyclase assay1. The authors proposed it as a molecular probe for melanotropin receptors on normal and melanoma melanocytes1.
In frog skin, melanophore dispersion after a single exposure persisted for weeks, far longer than with alpha-MSH or [Nle4]-alpha-MSH. In vitro work with lizard skin showed that this prolonged activity depended on extracellular calcium, which the authors linked to receptor signal transduction2.
What published studies have examined
Structure-activity work compared [Nle4, D-Phe7]-alpha-MSH with alpha-MSH and [Nle4]-alpha-MSH for enzymatic stability, frog skin darkening, mouse melanoma adenylate cyclase and tyrosinase activity1. Prolonged melanophore dispersion and its calcium dependence were examined in frog and lizard skin2.
A toxicology study in mice examined organs, haematological indices, weight gain, behaviour and serum cortisol, and measured diffusion through mouse skin in vitro3.
Sources [3]
Two multicentre, randomised, double-blind, placebo-controlled trials of afamelanotide in erythropoietic protoporphyria used the number of hours of direct sunlight exposure without pain as the primary efficacy end point (NCT01605136 and NCT00979745)5. A review describes the wider clinical history of melanotan I and melanotan II4.
4-Norleucine, 7-D-phenylalanine-alpha-melanocyte-stimulating hormone: a highly potent alpha-melanotropin with ultralong biological activity.
Sawyer TK, Sanfilippo PJ, Hruby VJ, et al. Proceedings of the National Academy of Sciences of the United States of America, 1980.
Calcium-dependent prolonged effects on melanophores of [4-norleucine, 7-D-phenylalanine]-alpha-melanotropin.
Hadley ME, Anderson B, Heward CB, et al. Science, 1981.
Toxicologic studies of a superpotent alpha-melanotropin, [Nle4, D-Phe7]alpha-MSH.
Dorr RT, Dawson BV, al-Obeidi F, et al. Investigational New Drugs, 1988.
Melanocortin peptide therapeutics: historical milestones, clinical studies and commercialization.
Hadley ME, Dorr RT Peptides, 2006.
Afamelanotide for Erythropoietic Protoporphyria.
Langendonk JG, Balwani M, Anderson KE, et al. The New England Journal of Medicine, 2015.
This page is provided for research and educational reference only. It does not constitute medical advice, dosing guidance, or a recommendation for use. All compounds are strictly for laboratory and in-vitro research purposes.