Glutamine transport in renal basolateral vesicles from dogs with metabolic acidosis.
Glutamine transport in renal basolateral vesicles from dogs with metabolic acidosis.
复制标题
代谢性酸中毒犬肾基底外侧囊泡中谷氨酰胺的转运。
DOI：
10.1152/ajprenal.1984.246.1.f78
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
Hammerman,MR
中科院分区：
文献类型：
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作者：
Windus,DW;Cohn,DE;Klahr,S;Hammerman,MR
为了确定慢性代谢性酸中毒中每个肾单位氨产量的增加是否伴随着L-谷氨酰胺跨肾皮质细胞基底外侧膜转运的增加以及由此产生的这种产氨氨基酸的可用性增加，我们测量了从正常和酸中毒犬肾脏分离的基底外侧膜囊泡（BLMV）中的L-[3 H]谷氨酰胺转运。在来自正常犬肾脏的BLMV中证明了L-[3 H]谷氨酰胺的Na+依赖性产电转运，其在25 μ M至2 mM L-谷氨酰胺的浓度范围内表现出饱和性。表观Km为416 +/- 114 microM，Vmax为536 +/- 129 pmol X mg蛋白-1 X 15 s-1。Na+依赖性L-[3 H]谷氨酰胺转运的初始速率在酸中毒犬肾脏BLMV中增加，表现为表观Vmax增加。我们的结论是，适应导致更大的摄取L-谷氨酰胺跨基底外侧膜的肾皮质细胞可能是基础，在一定程度上，增加氨生产率每肾单位看到慢性代谢性酸中毒。
To determine whether the increased ammonia production per nephron in chronic metabolic acidosis is accompanied by augmented L-glutamine transport across the basolateral membrane of the renal cortical cell and consequent increased availability of this ammoniagenic amino acid, we measured L-[3H]glutamine transport in basolateral membrane vesicles (BLMV) isolated from kidneys of normal and acidotic dogs. Na+ -dependent electrogenic transport of L-[3H]glutamine was demonstrated in BLMV from kidneys of normal dogs that exhibited saturability over the concentration range of 25 microM to 2 mM L-glutamine. The apparent Km was 416 +/- 114 microM and Vmax was 536 +/- 129 pmol X mg protein-1 X 15 s-1. The initial rate of Na+ -dependent L-[3H]glutamine transport was increased in BLMV from kidneys of acidotic dogs, as reflected by an increased apparent Vmax. We conclude that an adaptation resulting in greater uptake of L-glutamine across the basolateral membrane of the renal cortical cell may underlie, in part, the increased rate of ammonia production per nephron seen in chronic metabolic acidosis.