Nonapeptide-1

Nonapeptide-1 (Melanostatine-5), a peptide hormone, is a selective antagonist of MC1R (K_i: 40 nM). Nonapeptide-1 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 inhibits melanin synthesis, and can be used in the research of skin pigmentation and regulation of steroid production in the adrenal gland, skin cancer^[1][2][3]. In Vitro: Nonapeptide-1 (153N-6) inhibits α-melanocyte hormone (α-MSH)-induced melanosome dispersion, with an IC₅₀ value of 11 nM^[1].
Nonapeptide-1 (0.1 nM-1 μΜ, 30 min) inhibits α-MSH-induced intracellular cAMP levels in melanocytes, with an IC₅₀ of 2.5 nM^[1].
Nonapeptide-1 (153N-6) shows highest affinity for MC1R (K_i: 40 nM) in COS-1 cells expressing human receptors, and is selective for MC1R over MC3R, MC4R, and MC5R (K_i: 0.47, 1.34, and 2.4 μΜ, respectively)^[2].
Nonapeptide-1 (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^[3].
Nonapeptide-1 (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^[3].