Sodium-dependent, concentrative nucleoside transport in Walker 256 rat carcinosarcoma cells.
Sodium-dependent, concentrative nucleoside transport in Walker 256 rat carcinosarcoma cells.
复制标题
Walker 256 大鼠癌肉瘤细胞中钠依赖性集中核苷转运。
DOI：
10.1016/0006-291x(91)91642-p
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发表时间：
1991
影响因子：
3.1
通讯作者：
Belt,JA
中科院分区：
文献类型：
--
作者：
Crawford,CR;Belt,JA
使用福霉素 B（肌苷的非代谢类似物）重新检查 Walker 256 细胞中的核苷转运。在双嘧达莫抑制先前在这些细胞中描述的平衡（易化扩散）转运蛋白的情况下，1 μM 福霉素 B 的初始摄取速率在含 Na+ 培养基中比在无 Na+ 培养基中高 10 倍。在Na + 和双嘧达莫存在的情况下，福霉素B的细胞内浓度在一分钟内超过培养基中的浓度，并且在5分钟内比培养基中的浓度高6倍。福霉素 B 的 Na+ 依赖性转运被低浓度的肌苷抑制，但胸苷不被抑制。此外，在双嘧达莫存在的情况下，尿苷而非胸苷的 Na+ 依赖性转运是明显的。这些数据表明，Walker 256 细胞除了先前描述的平衡转运蛋白外，还具有浓缩核苷转运蛋白。该转运蛋白的特异性似乎与先前在小鼠肠上皮细胞中描述的两种 Na+ 依赖性转运蛋白之一相对应。
Nucleoside transport in Walker 256 cells was reexamined using formycin B, a nonmetabolized analog of inosine. In the presence of dipyridamole to inhibit the equilibrative (facilitated diffusion) transporter previously described in these cells, the initial rate of uptake of 1 μM formycin B was 10-fold greater in Na+-containing medium than in Na+-free medium. In the presence of Na+and dipyridamole the intracellular concentration of formycin B exceeded that in the medium within one min and was 6-fold greater than that of the medium by 5 min. Na+-dependent transport of formycin B was inhibited by low concentrations of inosine, but not thymidine. Furthermore, Na+-dependent transport of uridine, but not thymidine, was apparent in the presence of dipyridamole. These data indicate that Walker 256 cells have, in addition to the previously described equilibrative transporter, a concentrative mucleoside transporter. The specificity of this transporter appears to correspond to one of the two Na+-dependent transporters previously described in mouse intestinal epithelial cells.