Ionic requirements for taurocholate transport in rat liver plasma membrane vesicles.
Ionic requirements for taurocholate transport in rat liver plasma membrane vesicles.
复制标题
大鼠肝质膜囊泡中牛磺胆酸盐转运的离子需求。
DOI：
10.1007/bf00743242
复制
发表时间：
1984
影响因子：
3
通讯作者：
Fleischer,S
中科院分区：
文献类型：
--
作者：
Simion,FA;Fleischer,B;Fleischer,S
作为肠肝循环的一部分，牛磺胆酸盐通过 Na+ 梯度依赖性、载体介导的过程被肝细胞吸收。牛磺胆酸盐吸收对 Na+ 梯度存在的依赖性（外部大于内部）已在离体大鼠肝脏质膜中进行了研究。钠的吸收是特异性的，并且发现每吸收牛磺胆酸盐的共转运化学计量为 2 Na+。还发现囊泡内 K+ 离子的存在对于 Na+ 刺激的牛磺胆酸盐的最大吸收至关重要，尽管 K+ 梯度不是必需的。在这方面，Mg2+ 几乎与 K+ 一样有效。 Na + 和牛磺胆酸盐在摄取过程中的共存被证明是生电的，因此 K + 可以充当交换抗衡离子，防止囊泡内正电荷的积累。
As part of the enterohepatic circulation, taurocholate is taken up by hepatocytes by a Na+-gradient-dependent, carrier-mediated process. The dependence of taurocholate uptake on the presence of a Na+gradient, outside greater than inside, has been studied in isolated rat liver plasma membranes. The uptake is specific for sodium, and a cotransport stoichiometry of 2 Na+per taurocholate taken up was found. The presence of K+ions inside the vesicles was also found to be essential for maximum Na+-stimulated uptake of taurocholate, although a K+gradient is not required. Mg2+was almost as effective as K+in this regard. The symport of Na+and taurocholate during uptake was shown to be electrogenic, so that K+may act as an exchange counterion preventing the accumulation of positive charge within the vesicles.