Melanocyte-stimulating hormone and the regulation of tyrosinase activity in hair follicular melanocytes of the mouse.

摘要: Skin tyrosinase activity increases during hair growth in C3H-HeAvy mice and reaches higher levels young (30- to 35-day-old) when the follicular melanocytes synthesize black pigment, eumelanin, than older (6-month-old) they produce golden yellow phaeomelanin. To examine regulation of at these different stages we have compared effect alpha-MSH other agents that act, through cyclic AMP-dependent mechanisms, on skin both old growth, initiated by plucking. Daily administration alpha-MSH, isoprenaline or theophylline increased coat darkness, younger 7-9 days after plucking, but were ineffective mice. Similarly 8-bromo-cyclic AMP explants from incubated for up 24 h had no Cyclic GMP It is suggested whereas mechanisms may operate regulate eumelanin systems not Phaeomelanin synthesis, unlike depend upon its this could explain low enzyme failure respond activators system periods phaeomelanin production.