Wilson F A, Treanor L L
Gastroenterology. 1981 Jul;81(1):54-60.
Studies were performed to determine relationships among Na+, K+-ATPase, the transmucosal Na+ gradient, and bile-acid transport in metabolically viable cells isolated from rat ileum. Incubation of cells with 0, 10(-6), 10(-5), 10(-4) and 10(-3) M ouabain resulted, respectively, in a 0, 10.3, 42.1, 97.0, and 100% decrease in glycocholate uptake and a 0, 10.7, 46.4, 76.8, and 100% decrease in Na+, K+-ATPase activity. Thus, one-half maximal inhibition of glycocholate uptake and Na+, K+-ATPase activity occurred at 5.5 x 10(-5) M and 1.7 x 10(-5) M ouabain, respectively. A change in glycocholate uptake was correlated with a change in Na+, K+-ATPase activity after daily injections of methylprednisolone. After 4 days treated animals showed a 26% and 36% increase in glycocholate uptake and Na+, K+-ATPase activity, respectively, over pair-fed saline-treated controls (p less than 0.001). Methylprednisolone did not significantly alter the activity of (Mg++)-ATPase when compared with controls (p greater than 0.05). Glycocholate uptake was reduced by the omission of Na+ from the incubation medium. Preincubation of cells at 37 degrees C with gramicidin D, 10 micrograms/ml, to alter membrane permeability to Na+, resulted in a significant rise in cell Na+ (p less than 0.01) and a significant fall in glycocholate uptake from values in untreated cells (p less than 0.01) to approach values for glycocholate uptake at 0 degrees C. These data suggest that Na+, K+-ATPase may play a role in a bile-acid uptake into ileal cells possibly by maintaining a Na+ electrochemical potential gradient for coupled Na+-bile-acid transport.
开展了多项研究，以确定从大鼠回肠分离出的代谢活性细胞中钠钾 -ATP 酶、跨黏膜钠梯度和胆汁酸转运之间的关系。用 0、10⁻⁶、10⁻⁵、10⁻⁴ 和 10⁻³ M 的哇巴因孵育细胞，分别导致甘氨胆酸盐摄取减少 0、10.3%、42.1%、97.0% 和 100%，钠钾 -ATP 酶活性降低 0、10.7%、46.4%、76.8% 和 100%。因此，甘氨胆酸盐摄取和钠钾 -ATP 酶活性的半数最大抑制分别发生在 5.5×10⁻⁵ M 和 1.7×10⁻⁵ M 的哇巴因浓度下。每日注射甲基强的松龙后，甘氨胆酸盐摄取的变化与钠钾 -ATP 酶活性的变化相关。处理 4 天后，与成对喂食盐水处理的对照组相比，动物的甘氨胆酸盐摄取和钠钾 -ATP 酶活性分别增加了 26% 和 36%（p < 0.001）。与对照组相比，甲基强的松龙对（Mg²⁺）-ATP 酶的活性没有显著影响（p > 0.05）。孵育培养基中省略钠离子会降低甘氨胆酸盐的摄取。用 10 微克/毫升的短杆菌肽 D 在 37℃ 预孵育细胞以改变细胞膜对钠离子的通透性，导致细胞内钠离子显著升高（p < 0.01），甘氨胆酸盐摄取从未处理细胞的值显著下降（p < 0.01），接近 0℃ 时甘氨胆酸盐摄取的值。这些数据表明，钠钾 -ATP 酶可能通过维持用于耦合钠 - 胆汁酸转运的钠电化学势梯度，在胆汁酸进入回肠细胞的过程中发挥作用。
