Jakobs E S, Paterson A R
Biochem Biophys Res Commun. 1986 Nov 14;140(3):1028-35. doi: 10.1016/0006-291x(86)90738-2.
In a simple salts medium, monolayers of IEC-6 intestinal cells achieved concentrations of unmetabolized formycin B (an analog of inosine) about 6-fold higher than in the medium. Rates of formycin B influx were a saturable function of Na+ concentrations in the medium. Although IEC-6 cells possess sites with high affinity for nitrobenzylthioinosine, a potent inhibitor of equilibrative (facilitated diffusion) nucleoside transport systems in certain cell types, the inhibitor had only minor effects on formycin B uptake in IEC-6 cells, but reduced efflux of the analog from these cells. These findings indicate the joint presence in IEC-6 cells of nucleoside transporters of two types, one that is concentrative and Na+-dependent, and another that is sensitive to nitrobenzylthioinosine and apparently equilibrative.
在简单盐类培养基中，IEC - 6肠细胞单层对未代谢的间型霉素B（肌苷类似物）的富集浓度比培养基中的浓度高约6倍。间型霉素B的内流速率是培养基中Na⁺浓度的饱和函数。尽管IEC - 6细胞具有对硝基苄硫基肌苷（在某些细胞类型中是平衡型（易化扩散）核苷转运系统的强效抑制剂）具有高亲和力的位点，但该抑制剂对IEC - 6细胞摄取间型霉素B仅有轻微影响，但减少了该类似物从这些细胞中的外流。这些发现表明，IEC - 6细胞中同时存在两种类型的核苷转运体，一种是浓缩型且依赖Na⁺的，另一种对硝基苄硫基肌苷敏感且显然是平衡型的。
