Transport of carboxylic acids by renal membrane vesicles.
Transport of carboxylic acids by renal membrane vesicles.
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DOI：
10.1146/annurev.ph.47.030185.001015
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发表时间：
1985
影响因子：
18.2
通讯作者：
E. M. Wright
中科院分区：
文献类型：
--
作者：
E. M. Wright
肾脏积极代谢Krebs循环中间产物、短链脂肪酸和酮体（12，41）。血浆中的这些中间产物被肾小球过滤并保存在近端小管中。与糖和氨基酸不同，直到最近才对羧酸的肾脏处理知之甚少。原因之一是这些底物的高代谢率和缺乏非代谢类似物。随着来自肾皮质的膜囊泡制剂的出现（见31），在没有代谢的情况下检查羧酸的膜转运成为可能。在这篇评论中，我将总结工作的羧酸运输使用囊泡制剂。在刷状边界，两个不同的钠共转运系统已被发现：一个为单羧酸，另一个为克雷布斯循环中间体。在肾基底外侧膜中也发现了二羧酸和三羧酸的钠共转运系统。另一方面，基底外侧单羧酸转运仅通过易化扩散锡永发生。Krebs循环中间体、短链羧酸和酮体的血浆水平范围为0.01 mM至1.5 mM（17）。然而，该水平可以随着酸碱状态、饮食、糖尿病和饥饿而变化很大。例如，β-羟基丁酸水平在饥饿时从1 mM增加到6 mM，柠檬酸盐随着酸碱状态的变化在0.09 mM和0.15 mM之间变化。所有这些都是自由过滤的，但尿排泄量仅为过滤负荷的3-35%。重吸收发生在近端小管（见40、45）。标记为Excre-
The kidney avidly metabolizes Krebs-cycle intermediates, short-chain fatty acids, and ketone bodies (12, 41). These intermediates in plasma are filtered by the glomerulus and conserved in the proximal tubule. Unlike sugars and amino acids, relatively little was known about the renal handling of carboxylic acids until recently. One reason was the high rates of metabolism of these substrates and the lack of nonmetabolized analogs. With the advent of membrane vesicle preparations from the renal cortex (see 31), it became possible to examine membrane transport of the carboxylic acids in the absence of metabolism. In this review I will summarize work on the transport of carboxylic acids using vesicle preparations. In brush borders, two distinct Na-cotransport systems have been uncovered: one for monocarboxylic acids, and another for Krebs cycle intermediates. A Na-cotransport system for the diand tri-carboxylic acids is also found in renal basolateral membranes. On the other hand, the basolateral monocarboxylic-acid transport occurs simply by facilitated diffu SIOn. The plasma levels of Krebs-cycle intermediates, short-chain carboxylic acids, and ketone bodies range from 0.01 mM to 1.5 mM (17). However, the levels can vary widely with acid-base status, diet, diabetes, and starvation. For example, (3-hydroxybutyrate levels increase from 1 mM to 6 mM on starvation, and citrate varies between 0.09 mM and 0.15 mM with changes in acid-base status. All are freely filtered, but urinary excretion is only 3-35% of the filtered load. Reabsorption occurs in the proximal tubule (see 40,45). Marked excre-