Na+ pump in renal tubular cells is regulated by endogenous Na+-K+-ATPase inhibitor from hypothalamus.
Na+ pump in renal tubular cells is regulated by endogenous Na+-K+-ATPase inhibitor from hypothalamus.
复制标题
肾小管细胞中的钠泵受下丘脑内源性 Na -K -ATP 酶抑制剂的调节。
DOI：
10.1152/ajprenal.1988.255.4.f574
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
HaupertJr,GT
中科院分区：
文献类型：
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作者：
Cantiello,HF;Chen,E;Ray,S;HaupertJr,GT
牛下丘脑含有一种高亲和力、特异性、可逆的哺乳动物Na ~+-K ~+-ATP酶抑制剂。使用分离的膜组分的动力学分析表明，下丘脑因子（HF）的结合和解离速率（如哇巴因）相对较长（关闭速率= 60分钟）。为了确定是否在完整的细胞中的抑制动力学可能更符合体内生理过程的调节，HF在完整的肾上皮细胞（LLC-PK 1）的结合和解离反应进行了研究，使用86 Rb+摄取和[3 H]哇巴因结合。与膜一样，用HF孵育60分钟抑制LLC-PK 1细胞中的Na+-K+-ATP酶。与膜研究相反，不需要与LLC-PK 1长时间孵育来观察Na+-K+-ATP酶的抑制。HF引起了33%的抑制哇巴因敏感的86 Rb+流入10分钟内。孵育的细胞与HF，然后冲洗显示泵抑制和泵活性的两倍迅速逆转。HF抑制LLC-PK 186 Rb+摄取的剂量-反应曲线显示与变构结合反应一致的S形形状。因此，HF是完整肾细胞中Na+-K+-ATP酶活性的有效调节剂，结合和解离反应与相关生理过程一致。
Bovine hypothalamus contains a high affinity, specific, reversible inhibitor of mammalian Na+-K+-ATPase. Kinetic analysis using isolated membrane fractions showed binding and dissociation rates of the hypothalamic factor (HF) to be (like ouabain) relatively long (off rate = 60 min). To determine whether the kinetics of inhibition in intact cells might be more consistent with regulation of physiological processes in vivo, binding and dissociation reactions of HF in intact renal epithelial cells (LLC-PK1) were studied using 86Rb+ uptake and [3H]ouabain binding. As with membranes, a 60-min incubation with HF inhibited Na+-K+-ATPase in LLC-PK1 cells. In contrast to membrane studies, no prolonged incubation with LLC-PK1 was needed to observe inhibition of Na+-K+-ATPase. HF caused a 33% inhibition of ouabain-sensitive 86Rb+ influx within 10 min. Incubation of cells with HF followed by washout showed rapid reversal of pump inhibition and a doubling of pump activity. The dose-response curve for HF inhibition of LLC-PK1 86Rb+ uptake showed a sigmoidal shape consistent with an allosteric binding reaction. Thus HF is a potent regulator of Na+-K+-ATPase activity in intact renal cells, with binding and dissociation reactions consistent with relevant physiological processes.