Citrate uptake by basolateral and luminal membrane vesicles from rabbit kidney cortex.
Citrate uptake by basolateral and luminal membrane vesicles from rabbit kidney cortex.
复制标题
兔肾皮质基底外侧和腔膜囊泡对柠檬酸盐的摄取。
DOI：
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发表时间：
1983
影响因子：
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通讯作者：
M. Sheikh
中科院分区：
文献类型：
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作者：
K. Jørgensen;U. Kragh‐Hansen;H. Røigaard;M. Sheikh
在各种实验条件下，研究了柠檬酸盐在肾基底外侧膜囊泡和腔膜囊泡中的肾小管转运机制。两种膜制剂通过Na+依赖性转运系统吸收柠檬酸盐，但具有不同的特性。基底外侧膜囊泡对柠檬酸盐的摄取对膜电位的变化不敏感，这表明阴离子的电中性转运。Na+依赖性摄取柠檬酸盐的管腔膜囊泡的影响，存在的Na+盐阴离子的不同渗透性的顺序：氯大于硫酸盐大于葡萄糖酸盐。此外，柠檬酸盐的膜囊泡电位敏感染料悬浮液中的添加导致的染料，指示该化合物的产电转移的光学变化。与基底外侧膜囊泡相反，位于管腔膜囊泡中的柠檬酸盐转运系统的表观亲和力对介质pH值的变化敏感，并且在研究的pH值范围内高于基底外侧膜囊泡。在此基础上，提出了一个家兔肾近曲小管转运柠檬酸盐的模型。
The mechanisms of tubular transport of citrate in renal basolateral and luminal membrane vesicles were studied under various experimental conditions. Both membrane preparations take up citrate by a Na+-dependent transport system, although with different characteristics. The uptake of citrate by basolateral membrane vesicles was insensitive to changes in membrane potential, which is indicative of electroneutral transport of the anion. The Na+-dependent uptake of citrate by luminal membrane vesicles was influenced by the presence of Na+salt anions of different permeabilities in the order: chloride greater than sulfate greater than gluconate. Furthermore, addition of citrate to membrane vesicle-potential-sensitive dye suspensions resulted in optical changes of the dye, indicative of electrogenic transfer of this compound. The apparent affinity of the citrate transport system located in luminal membrane vesicles, in contrast to basolateral membrane vesicles, was sensitive to changes in medium pH and was higher than that of basolateral membrane vesicles in the pH range studied. On the basis of these results a model for the transport of citrate by rabbit kidney proximal tubule is proposed.