MT-II activates MC1R on melanocytes, triggering the intracellular signaling cascade (cAMP → CREB → MITF → tyrosinase) that drives melanin production. In cell culture models, MT-II treatment increases both the quantity and type of melanin produced, shifting the ratio toward eumelanin (the darker, photoprotective form) relative to pheomelanin.1
The pigmentation research has generated interest in MT-II as a tool for studying the molecular controls of human skin color, UV-damage susceptibility, and melanocyte biology.
