THYROID HORMONES-CELL INTERACTIONS

我们在立体定向，能量依赖 转运到培养的细胞中解决了几个问题。 胶质瘤 细胞被证明具有最活跃的质膜转运 所有我们检测过的细胞的T4 这并没有伴随着 通过在细胞核中的类似摄取，表明 这些细胞中的甲状腺激素转运，可能与 从毛细血管内皮到神经元的跨细胞通道。 在 神经母细胞瘤细胞，我们证明了质膜转运， T_4和T_3的抑制作用可被生理浓度的 L-系统氨基酸，特别是苯丙氨酸。 研究 亲和标记神经母细胞瘤膜蛋白 甲状腺激素的溴乙酰衍生物至少鉴定出2种 蛋白质（24 kDa和29 kDa）以前未在其他细胞中发现 类型 24 kDa蛋白与L-T3的反应更强， 29 kDa蛋白与D-T3。 一类新的拟甲状腺药物， 在体内对肝脏和心脏有不同的影响， 对T3转运到肝癌细胞中发挥不同的作用， 成肌细胞 这可以解释在体内观察到的效应。

A continuation of our work on the stereospecific, energy-dependent transport into cultured cells addressed several issues. Glioma cells were shown to have the most active plasma membrane transport of T4 of any cells that we have examined. This was not accompanied by comparable uptake in the nuclei, suggesting a special role for thyroid hormone transport in these cells, possibly related to transcellular passage from capillary endothelium to neurons. In neuroblastoma cells, we demonstrated that plasma membrane transport of both T4 and T3 was inhibited by physiological concentrations of L-system amino acids, notably phenylalanine. A study of neuroblastoma membrane proteins by affinity labeling with bromoacetyl derivatives of thyroid hormones identified at least 2 proteins (24 kDa and 29 kDa) not previously found in other cell types. The 24 kDa protein reacted more strongly with L-T3 and the 29 kDa protein with D-T3. A novel class of thyromimetics shown to have differential effects on liver and heart in vivo was found to exert a differential effect on T3 transport into hepatoma cells and myoblasts. This may explain the effects observed in vivo.