Nonapeptide-1 (Melanostatine-5) acetate salt, a peptide hormone, is a selective antagonist of MC1R (Ki: 40 nM). Nonapeptide-1 acetate salt is a competitive α-MSH antagonist that potently inhibits intracellular cAMP and melanosome dispersion induced by α-MSH in melanocytes (IC50: 2.5 nM and 11 nM, respectively). Nonapeptide-1 acetate salt inhibits melanin synthesis, and can be used in the research of skin pigmentation and regulation of steroid production in the adrenal gland, skin cancer[2].In Vitro: Nonapeptide-1 acetate salt (153N-6) inhibits α-melanocyte hormone (α-MSH)-induced melanosome dispersion, with an IC50 value of 11 nM.
Nonapeptide-1 acetate salt (0.1 nM-1 μΜ, 30 min) inhibits α-MSH-induced intracellular cAMP levels in melanocytes, with an IC50 of 2.5 nM.
Nonapeptide-1 acetate salt (153N-6) shows highest affinity for MC1R (Ki: 40 nM) in COS-1 cells expressing human receptors, and is selective for MC1R over MC3R, MC4R, and MC5R (Ki: 0.47, 1.34, and 2.4 μΜ, respectively)[2].
Nonapeptide-1 acetate salt (N-1A, 20 μΜ, 3 days) inhibits the basal melanin synthesis and reverses UVA-induced melanin increase in Human epidermal melanocytes (HEM cells) and HaCaT cells.
Nonapeptide-1 acetate salt (20 μΜ, 3 days) competes with α-MSH and downregulates the expression of MC1R, tyrosinase, TRP1, TRP2, and MITF via binding to MC1R in HaCaT cells and HEM cells.