Na+-independent L-arginine transport in rabbit renal brush border membrane vesicles.
Na+-independent L-arginine transport in rabbit renal brush border membrane vesicles.
复制标题
兔肾刷状缘膜囊泡中不依赖 Na 的 L-精氨酸转运。
DOI：
10.1016/0005-2736(82)90036-0
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发表时间：
1982
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：
Hammerman,MR
研究了兔肾刷状缘膜小泡对Na+非依赖性精氨酸的摄取。研究发现，随着囊外渗透压的增加，l-精氨酸的稳态摄取减少，并且在囊泡与l-精氨酸预孵卵后，囊泡表现出加速的交换扩散，而不是-精氨酸，这表明刷状边界囊泡对l-精氨酸的摄取反映了载体介导的向囊泡内空间的运输。在与赖氨酸和鸟氨酸预孵育的囊泡中，精氨酸的交换扩散加速，但不包括丙氨酸和脯氨酸，这表明肾刷状缘膜中存在二碱性氨基酸转运体。在水珠外[精氨酸]的初始转运速率为0.005 ~ 1.0 mm时，发现了部分饱和。水珠外双碱性氨基酸抑制了l-精氨酸的摄取，这与存在类似结构的水珠外氨基酸时对l-丙氨酸、l-谷氨酸、甘氨酸或l-脯氨酸的Na+非依赖性摄取不同。施加H+梯度（囊内pH<囊外pH）可增加l-精氨酸的摄取，FCCP可进一步增加H+梯度刺激的摄取。这些发现表明，在刷状边缘膜囊泡中，精氨酸的膜电位敏感、不依赖于Na+的转运不同于中性和酸性氨基酸的不依赖于Na+的转运。膜囊泡中不依赖于Na+的二碱性氨基酸运输可能反映了不依赖于Na+的二碱性氨基酸在肾刷状缘膜上的运输。
Na+-independentl-arginine uptake was studied in rabbit renal brush border membrane vesicles. The finding that steady-state uptake ofl-arginine decreased with increasing extravesicular osmolality and the demonstration of accelerative exchange diffusion after preincubation of vesicles withl-arginine, but notd-arginine, indicated that the uptake ofl-arginine in brush border vesicles was reflective of carrier-mediated transport into an intravesicular space. Accelerative exchange diffusion ofl-arginine was demonstrated in vesicles preincubated withl-lysine andl-ornithine, but notl-alanine orl-proline, suggesting the presence of a dibasic amino acid transporter in the renal brush border membrane. Partial saturation of initial rates ofl-arginine transport was found with extravesicular [arginine] varied from 0.005 to 1.0 mM.l-Arginine uptake was inhibited by extravesicular dibasic amino acids unlike the Na+-independent uptake ofl-alanine,l-glutamate, glycine orl-proline in the presence of extravesicular amino acids of similar structure.l-Arginine uptake was increased by the imposition of an H+gradient (intravesicular pH<extravesicular pH) and H+gradient stimulated uptake was further increased by FCCP. These findings demonstrate membrane-potential-sensitive, Na+-independent transport ofl-arginine in brush border membrane vesicles which differs from Na+-independent uptake of neutral and acidic amino acids. Na+-independent dibasic amino acid transport in membrane vesicles is likely reflective of Na+-independent transport of dibasic amino acids across the renal brush border membrane.