We investigated the structure-activity relationships of α-MSH (α-melanocyte stimulating hormone) fragment derivatives of the generic formulae Ac-α-MSH(x-13)-NH2 and Ac-α-MSH(6-x)-NH2. The minimal C-terminal sequences required for melanotropic activity were 8-13 and 7-13, respectively, in the frog and lizard skin bioassays. The Arg8-Trp9 sequence appears to be a fundamental component of the minimal message sequences found to date such as α-MSH(6-9), α-MSH(8-13) and α-MSH(7-13). We discovered that Ac-α-MSH(7-10)-NH2 was a weak and selective α-MSH antagonist on the lizard skin bioassay. Analysis of α-MSH(7-10) analogues of the generic formula Ac-Xaa-Arg-Trp-Yaa-NH2 led to Ac-[D-Trp7,D-Phe10]α-MSH(7-10)-NH2, a moderately potent, specific and competitive inhibitor of α-MSH in both the frog and the lizard skin bioassays.
- Message sequences
- α-MSH inhibitors
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience