Slominski A, Pawelek J
Department of Dermatology, Yale University School of Medicine, New Haven, Connecticut 06510.
Biosci Rep. 1987 Dec;7(12):949-54. doi: 10.1007/BF01122128.
Bomirski Ab amelanotic melanoma cells have recently been shown to undergo striking phenotypic changes when precursors of the melanogenic pathway, L-tyrosine and L-dopa, are added to the culture medium. The changes include increased tyrosinase activity and de novo synthesis of melanosomes and melanin. L-tyrosine and L-dopa appeared to elicit these responses through separate but overlapping regulatory pathways. Here we show an additional effect of L-tyrosine: stimulation of MSH binding capacity. Cells cultured for 24-48 hours in the presence of 200 microM L-tyrosine display a 3-4 fold increase in their ability to bind 125I-beta-MSH. L-dopa did not stimulate MSH binding under the same conditions. In control experiments neither L-tyrosine nor L-dopa had any effect on insulin binding. The amelanotic cells respond to MSH with increased dendrite formation, increased tyrosinase activity without melanin production, and decreased growth rate.
最近研究表明，当在培养基中添加黑色素生成途径的前体L-酪氨酸和L-多巴时，博米尔斯基无黑色素黑色素瘤细胞会发生显著的表型变化。这些变化包括酪氨酸酶活性增加以及黑素小体和黑色素的从头合成。L-酪氨酸和L-多巴似乎通过独立但重叠的调节途径引发这些反应。在此，我们展示了L-酪氨酸的另一种作用：刺激促黑素（MSH）结合能力。在200微摩尔L-酪氨酸存在下培养24至48小时的细胞，其结合125I-β-MSH的能力提高了3至4倍。在相同条件下，L-多巴并未刺激MSH结合。在对照实验中，L-酪氨酸和L-多巴对胰岛素结合均无任何影响。无黑色素细胞对MSH的反应是树突形成增加、酪氨酸酶活性增加但无黑色素生成以及生长速率降低。
