ION TRANSPORT BY THE CORTICAL COLLECTING DUCT

本提案的长期目标是在更大范围内了解 详细说明离子跨细胞转运的途径和调节机制 膜。 这项研究集中在肾集合管，因为这 结构已经开发出专门的运输系统来调节离子 排泄 例如，钠和氯排泄的调节， 在血压调节中的核心作用。 精确调节H+ 和钾排泄，以配合摄入量是至关重要的， 酸中毒（或酸中毒）和高钾血症（或低钾血症）。 收集管已经开发出调节吸收或吸收的系统。 每种离子的分泌。 概述的具体实验方法 在应用程序中将检查激素和autocoids 对一个或多个运输系统产生影响。 集合管离子 迁移可分为两大类：酸碱和氯离子 转运受闰细胞的影响，Na和K的转运受闰细胞的影响。 受主要细胞的影响。 申请的具体目的是： a）研究cAMP和主要信使 刺激插入细胞分泌H+和HCO 3; B）测定插入细胞的H+和HCO 3浓度， 激素和autocoids改变Na和K转运的机制， 主细胞;和c）确定氧化之间的联系 K-K交换模式中的Na-K泵的磷酸化和周转。 评价这些机制的方法包括 细胞内pH测量，细胞内电压测量， 等效电路和电缆分析，示踪通量测量，网络 Na、K、C1和HCO 3的运输测量和生化测量 单个肾单位节段。 结果将与我们的综合 了解盐和电解质平衡。 此外，他们还将在 对了解激素作用机制很重要。 最后， 这些实验可能会提供关于钠钾泵的方式的新见解， 可以通过激素和新陈代谢来调节。

The long term objectives of this proposal are to understand in greater detail the pathways and regulatory mechanisms of ion transport across cell membranes. The research focusses on the renal collecting duct because this structure has developed specialized transport systems to regulate ion excretion. The regulation of Na and Cl excretion, for example, plays a central role in the regulation of blood pressure. Precise regulation of H+ and K excretion in order to match intake is critical for prevention of acidosis (or alkalosis) and hyperkalemia (or hypokalemia), respectively. The collecting duct has developed systems to regulate the absorption or secretion of each ion species. Specific experimental approaches outlined in the application will examine the extent to which hormones and autocoids produce effects on one or more transport systems. Collecting duct ion transport can be divided into two general categories: acid-base and Cl transport is effected by intercalated cells, and Na and K transport is effected by principal cells. The specific aims of the application are to: a) investigate the mechanism(s) whereby cAMP and primary messengers stimulate H+ and HCO3 secretion by intercalated cells; b) determine the mechanisms where by hormones and autocoids alter Na and K transport by principal cells; and c) determine the linkage between oxidative phosphorylation and turnover of the Na-K pump in the K-K exchange mode. The methods to be used in the evaluation of these mechanisms include intracellular pH measurements, intracellular voltage measurements with equivalent circuit and cable analysis, tracer flux measurements, net transport measurements of Na, K, C1, and HCO3, and biochemical measurements in single nephron segments. The results will be relevant to our integrated understanding of salt and electrolyte balance. In addition, they will be important to the understanding of mechanisms of hormone action. Finally, the experiments may provide new insights regarding the ways the Na-K pump can be regulated both by hormones and by metabolism.