Taurocholate uptake by isolated skate hepatocytes: effect of albumin.
Taurocholate uptake by isolated skate hepatocytes: effect of albumin.
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分离的鳐鱼肝细胞摄取牛磺胆酸盐：白蛋白的作用。
DOI：
10.1152/ajpgi.1987.252.4.g479
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Boyer,JL
中科院分区：
文献类型：
--
作者：
Smith,DJ;Grossbard,M;Gordon,ER;Boyer,JL
牛磺胆酸盐转运分析了一个良好的特点，极化肝细胞制备的小滑冰（拉贾erinacea），一种无白蛋白血症的物种，不合成胆汁酸。此外，钠省略，牛白蛋白，卵清蛋白和牛γ-球蛋白对牛磺胆酸盐的摄取的影响进行了研究。摄取可分为非饱和（0.48 pmol X min-1 X mg蛋白-1）。microM-1）和可饱和组分（Km，32.5 microM和Vmax 110 pmol X min-1 X mg protein-1）。未获得钠依赖性证据。甘氨胆酸竞争性抑制牛磺胆酸摄取。磺溴酞、N-（4-叠氮基-2-硝基苯基）-2-氨基乙基磺酸盐和4，4 '-二异硫氰基苯乙烯-2，2'-二磺酸也可抑制牛磺胆酸盐摄取的初始速率，但不抑制乳酸盐或丙氨酸。白蛋白溶液中牛磺胆酸盐的肝脏摄取量（2.5%）是游离牛磺胆酸盐浓度估计值预期值的两倍。与此相反，等摩尔浓度的卵清蛋白或牛γ-球蛋白没有影响牛磺胆酸盐摄取率的测量和没有证据表明，可以找到一个特定的白蛋白受体在这些肝细胞上的125 I-白蛋白结合。这些研究表明，载体介导的，钠非依赖性的牛磺胆酸盐摄取转运系统存在于滑冰肝细胞中，这不仅仅是由牛磺胆酸盐的游离浓度驱动的。
Taurocholate transport was analyzed in a well characterized, polarized hepatocyte preparation from the small skate (Raja erinacea), an analbuminemic species that does not synthesize bile acids. In addition, the effect of sodium omission, bovine albumin, ovalbumin, and bovine gamma-globulin on the uptake of taurocholate was studied. Uptake could be divided into nonsaturable (0.48 pmol X min-1 X mg protein-1. microM-1) and saturable components (Km, 32.5 microM and Vmax 110 pmol X min-1 X mg protein-1). No evidence for sodium dependence could be obtained. Glycocholate competitively inhibited taurocholate uptake. The initial rate of taurocholate uptake was also inhibited by sulfobromophthalein, N-(4-azido-2-nitrophenyl)-2-aminoethyl sulfonate, and 4,4'-diisothiocyanostylbene-2,2'-disulfonic acid but not lactate or alanine. Hepatic uptake of taurocholate in albumin solutions (2.5%) was twice as great as expected from estimates of the free taurocholate concentration. In contrast, equimolar concentrations of ovalbumin or bovine gamma-globulin had no effect on measured rates of taurocholate uptake and no evidence for a specific albumin receptor could be found on these hepatocytes by 125I-albumin binding. These studies indicate that a carrier-mediated, sodium-independent transport system for taurocholate uptake is present in skate hepatocytes that is not driven solely by the free concentration of taurocholate.