TABLE 1

MC1R Affinity and Biologic Activity of α-MSH Analogs

MSH analogsIC50* (nmol/L)EC50† (pmol/L)
α-MSH1.19 ± 0.27‡66 ± 16.7‡
DOTA-NDP-MSH0.25 ± 0.02‡ND
MSHoct1.25 ± 0.08‡35.4 ± 9.1‡
DOTA-MSHoct9.21 ± 1.27354 ± 100

  • ↵* MC1R affinity of α-MSH analogs was assessed by competition binding experiments with B16F1 cells and 125I-NDP-MSH as radioligand (n = 3).

  • ↵† Biologic activity of α-MSH analogs was determined in melanin assay with B16F1 cells, and results are expressed as concentration inducing half-maximal response (EC50, n = 2–9).

  • ↵‡ P < 0.01 vs. DOTA-MSHoct.

  • ND = not determined.

  • Data are mean ± SEM.