ION TRANSPORT BY THE CORTICAL COLLECTING DUCT

这项建议的长期目标是更好地理解 详细介绍了离子跨细胞运输的途径和调控机制 膜。这项研究集中在肾脏集合管上，因为 Structure开发了专门的运输系统来调节离子 排泄物。例如，钠和氯排泄的调节在 在调节血压方面起着核心作用。H的精确调控 而钾的排出以匹配摄入量是预防糖尿病的关键 酸中毒(或碱中毒)和高钾血症(或低钾血症)。 收集管道已经开发了系统来调节吸收或 每种离子的分泌物。概述了具体的实验方法 将检测荷尔蒙和自体激素在多大程度上 对一个或多个运输系统产生影响。收集管道离子 运输可分为两大类：酸碱和氯 Na和K的转运是通过嵌插细胞来实现的。 受主细胞的影响。这项申请的具体目的是： A)调查cAMP和主要信使的机制(S) 刺激嵌入细胞分泌H和HCO3；b)测定 激素和自体激素改变钠和钾转运的机制 主细胞；以及c)确定氧化之间的联系 K-K交换模式下Na-K泵的磷酸化和周转。 评估这些机制所使用的方法包括 细胞内pH测量，细胞内电压测量 等值电路和电缆分析、示踪剂流量测量、净值 Na、K、Cl和HCO3的迁移测量和生化测量 在单个肾单位节段。结果将与我们的综合 了解盐和电解质的平衡。此外，他们将被 对于理解荷尔蒙的作用机制很重要。最后， 这些实验可能会为Na-K泵的方式提供新的见解 可以由荷尔蒙和新陈代谢来调节。

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.