p-Aminohippurate transport in basal-lateral membrane vesicles from rabbit renal cortex: stimulation by pH and sodium gradients.
p-Aminohippurate transport in basal-lateral membrane vesicles from rabbit renal cortex: stimulation by pH and sodium gradients.
复制标题
兔肾皮质基底侧膜囊泡中的对氨基马尿酸转运：pH 和钠梯度的刺激。
DOI：
10.1016/0005-2736(87)90444-5
复制
发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Eveloff,J
中科院分区：
文献类型：
--
作者：
Eveloff,J
本文研究了兔肾皮质基底-侧膜囊泡对氨基马尿酸（PAH）的摄取。一个向外定向的羟基梯度（pH o= 6.0，pH i= 7.6）刺激PAH的摄取略高于内部和外部的pH值相等时，在7.6。一个100 mM的葡萄糖酸钠梯度直接进入基底侧膜囊泡增加PAH摄取约2倍，当N-甲基-D-葡糖胺或葡萄糖酸钾梯度存在。当羟基和钠梯度同时施加（pH 0 = 6.0，pH i= 7.6和100 mM葡萄糖酸钠extravesicularly）PAH的吸收刺激大于与pH或Na+梯度单独。事实上，观察到了“过冲”。反转运实验表明，泡内PAH或泡内PAH和Na+均可刺激3 H-PAH的摄取。丙磺舒，有机阴离子转运的抑制剂，抑制羟基刺激和Na+梯度刺激PAH的摄取，但最大的抑制丙磺舒时，羟基和钠梯度都存在。因此，我们认为PAH在近端小管基底-侧膜上蓄积的驱动力是一个转运系统，该系统将Na+和PAH转移到细胞中，使氢氧根离子离开细胞，即钠依赖性阴离子-阴离子交换系统。
Abstract p-Aminohippuric acid (PAH) uptake was studied in basal-lateral membrane vesicles prepared from rabbit renal cortex. An outwardly directed hydroxyl gradient (pH o= 6.0, pH i= 7.6) stimulated PAH uptake slightly over that when the internal and external pH values were equal at 7.6. A 100 mM sodium gluconate gradient directed into the basal-lateral membrane vesicles increased PAH uptake about 2-fold over that when N-methyl-d-glucamine or potassium gluconate gradients were present. When hydroxyl and sodium gradients were simultaneously imposed (pH o= 6.0, pH i= 7.6 and 100 mM sodium gluconate extravesicularly) PAH uptake was stimulated greater than with the pH or Na+ gradient alone. In fact, an ‘overshoot’was observed. Countertransport experiments showed that either intravesicular PAH or intravesicular PAH and Na+ could stimulate 3 H-PAH uptake. Probenecid, an inhibitor of organic anion transport, inhibited both the hydroxyl-stimulated and Na+ gradient-stimulated PAH uptake but the greatest inhibition by probenecid was seen when the hydroxyl and sodium gradients were both present. Thus, it is proposed that the driving force for PAH accumulation across the basal-lateral membrane of the proximal tubule is a transport system which moves Na+ and PAH into the cell for an hydroxyl ion leaving the cell, ie a sodium-dependent anion-anion exchange system.