Endotelin-1 secretion and release by the keratinocytes Triggering of melanogenesis by the activation of endothelin-1 on the melanocytes / Melanocytes differenciation and proliferation Synthesis of melanin : activation of tyrosinase enzyme Transport of melanin into keratinocytes Coloration of melanin (oxidation) Migration of melanin Accumulation of melanin in stratum corneum pigmentation of the skin