Wilson M J, Spaziani E
Acta Endocrinol (Copenh). 1976 Feb;81(2):435-48. doi: 10.1530/acta.0.0810435.
Pigmentation of the scrotum of the black-pelted rat, as expressed through melanocyte melanogenic activity, is controlled by androgens. Castration decreased in vitro incorporation of [14C]tyrosine into melanin. Testosterone pre-treatment for 4 days increased malanin radioactivity over castrate cont rols; the increment in vitro was prevented by an inhibitor of protein systhesis (cycloheximide) added to the incubation. However, cycloheximide only partially blocked melanin synthesis when added to tissue from animals hromone treated for 6 days in vivo, and was ineffective in tissue from intacts. Bulk protein snthesis in vitro (incorporation of [14C]tyrosine or -leucine) was not affected by castration or testosterone treatment but was uniformly inhibited by cycloheximide. The data suggest that new synthesis of specific protein in vitro was necessary for initial hormone-stimulation of melanogenesis, but with longer exposure to hormone sufficient protein was pre-synthetized in vivo to permit melanogenesis during incubation with the inhibitor.
黑毛大鼠阴囊的色素沉着，通过黑素细胞的黑素生成活性来体现，受雄激素控制。去势会降低[14C]酪氨酸在体外掺入黑色素的量。睾酮预处理4天可使黑色素放射性高于去势对照组；在孵育过程中添加蛋白质合成抑制剂（环己酰亚胺）可阻止体外的增加。然而，当添加到体内经激素处理6天的动物组织中时，环己酰亚胺仅部分阻断黑色素合成，而对完整动物的组织无效。体外的大量蛋白质合成（[14C]酪氨酸或亮氨酸的掺入）不受去势或睾酮处理的影响，但均被环己酰亚胺抑制。数据表明，体外特定蛋白质的新合成对于激素对黑素生成的初始刺激是必要的，但随着激素暴露时间延长，体内已预先合成了足够的蛋白质，以允许在与抑制剂孵育期间进行黑素生成。
