Simion F A, Fleischer B, Fleischer S
J Bioenerg Biomembr. 1984 Dec;16(5-6):507-15. doi: 10.1007/BF00743242.
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.
作为肠肝循环的一部分，牛磺胆酸盐通过一种依赖于钠离子梯度、载体介导的过程被肝细胞摄取。在分离的大鼠肝细胞膜中，研究了牛磺胆酸盐摄取对钠离子梯度（细胞外高于细胞内）存在的依赖性。摄取对钠离子具有特异性，并且发现每摄取一个牛磺胆酸盐，共转运化学计量为2个钠离子。还发现囊泡内钾离子的存在对于最大程度地由钠离子刺激的牛磺胆酸盐摄取至关重要，尽管不需要钾离子梯度。在这方面，镁离子几乎与钾离子一样有效。摄取过程中钠离子和牛磺胆酸盐的同向转运被证明是生电的，因此钾离子可能作为交换抗衡离子，防止正电荷在囊泡内积累。
