Pathways for carboxylic acid transport by rabbit renal brush border membrane vesicles.
Pathways for carboxylic acid transport by rabbit renal brush border membrane vesicles.
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兔肾刷状缘膜囊泡的羧酸转运途径。
DOI：
10.1152/ajprenal.1982.243.5.f456
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
Wright,EM
中科院分区：
文献类型：
--
作者：
Nord,E;Wright,SH;Kippen,I;Wright,EM
采用钙沉淀法纯化兔肾皮质毛刷边界膜囊泡，并采用快速过滤法测定羧酸的摄取。l -乳酸、丙酮酸（单羧酸）和琥珀酸（二羧酸）表现出Na+共转运的特征：与无Na+对照条件相比，吸收Na+的初始速率（1秒）增强，向内呈Na+梯度，底物在囊泡内瞬间积累。l -乳酸盐和琥珀酸盐的动力学参数表明，每种底物都通过单一途径运输，并且两种底物表现出边际交叉抑制。包括丙酮酸和酮体在内的一系列单羧酸似乎与单羧酸载体相互作用。丙酮酸钠依赖的摄取动力学表明至少有两种运输途径，即，这种单羧酸盐同时具有单羧酸和二羧酸载体。我们得出结论，分离的兔肾微绒毛膜具有独立的单羧酸和多羧酸运输系统。
Brush border membrane vesicles were purified from rabbit renal cortex using a calcium-precipitation procedure, and the uptake of carboxylic acids was determined by a rapid-filtration method. L-Lactate, pyruvate (monocarboxylic acids), and succinate (dicarboxylic acid) demonstrated features of Na+ cotransport: enhanced initial rate (1 s) of uptake with an inward Na+ gradient compared with the Na+ -free control condition and transient accumulation of substrate within the vesicles. Kinetic parameters derived for L-lactate and succinate show that each substrate is transported via single pathway and that the two substrates exhibit marginal cross-inhibition. A range of monocarboxylic acids including pyruvate and ketone bodies appear to interact with the monocarboxylic acid carrier. The kinetics of Nat-dependent pyruvate uptake suggest at least two transport pathways-namely, that this monocarboxylate shares both the mono- and dicarboxylic acid carriers. We conclude that isolated rabbit renal microvillus membranes possess independent transport systems for mono- and polycarboxylic acids.