REGULATION OF URINARY ACIDIFICATION

尿液酸化的调节

• 批准号: 2139751
• 负责人: NEIL A KURTZMAN
• 金额: $ 21.07万
• 依托单位: TEXAS TECH UNIVERSITY HEALTH SCIS CENTER
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-01-01 至 1998-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2139751
• 关键词: acidity /alkalinity; adrenalectomy; aldosterone; alkalosis; amphotericin B; drug delivery systems; enzyme activity; hormone regulation /control mechanism; hypokalemia; kidney pharmacology; laboratory rabbit; laboratory rat; maleimides; phosphatase inhibitor; potassium; renal tubular transport; renal tubule acidosis; sodium potassium exchanging ATPase; toluene; urine acidity

The research proposed in this application deals with the control of urinary acidification in the collecting tubule (CT). We propose that this process is controlled by two pumps, an H-ATPase and an H-K-ATPase. We will characterize these pumps, both functionally and biochemically. Two hypotheses will be tested. Hypothesis I - Acidification in the CT is mediated by two proton pumps, an H-ATPase and an H-K-ATPase. The experiments testing this hypothesis will be performed in rat and rabbit nephron fragments. Considerable data concerning the H-ATPase is already available, much less is known about the H-K-ATPase. To show that these enzymes mediate distal acidification it is necessary to show that their activities change appropriately with acid-base perturbations and that their inhibition reduces acidification. We will study inhibition of the H-ATPase with bafilomycin A and N-ethylmaleimide; H-K-ATPase activity will be studied using vanadate, SCH28080, or K removal. The roles of aldosterone, K, and Cl in modulating enzyme activity will be examined. Hypothesis II - Inhibition of the H-K-ATPase results in hypokalemic distal renal tubular acidosis. These studies will be performed in rats and will employ clearance techniques, measurement of enzyme activities along the nephron, and functional studies in isolated tubules. We will study the effects of inhibiting the H-K-ATPase with vanadate and SCH28080. New data show, as predicted, that vanadate induces hypokalemic distal renal tubular acidosis. Other models of distal renal tubular acidosis will also be studied. By studying alterations in whole animal acid-base status and acid excretion, enzyme activities, net acidification in isolated tubules, and cell pH recovery when basolateral proton extension is blocked, we hope to elucidate the relationship between ATPase activity and tubular function.

本应用程序中提出的研究涉及 收集小管（CT）中的尿酸化。 我们提出了这一点 此过程由两个泵控制，一个HATPase和一个H-K-ATPase。 我们将在功能和生化上表征这些泵。 将检验两个假设。 CT中的假设I-酸化 由两个质子泵，一个HATPase和一个H-K-ATPase介导。 这 测试该假设的实验将在大鼠和兔子中进行 肾片段。 有关H-ATPase的大量数据已经 可用，对H-K-ATPase知之甚少。 表明这些 酶介导远端酸化，必须表明它们 活动随着酸碱扰动的适当变化，并且 它们的抑制作用减少了酸化。 我们将研究抑制 H-ATPase与Bafilomycin A和N-乙基马来酰亚胺； H-K-ATPase活性 将使用钒酸盐，SCH28080或k删除进行研究。 角色 将检查醛固酮，K和CL调节酶活性。 假设II-抑制H-K-ATPase会导致降低血压 肾远端肾小管酸中毒。 这些研究将在大鼠中进行 并将采用清除技术，测量酶活性 沿着肾单位和孤立小管中的功能研究。 我们将 研究用钒酸盐抑制H-K-ATPase的影响 SCH28080。 如预测的那样，新的数据表明，杂质诱发降低性降低症 肾远端肾小管酸中毒。其他远端肾小管的模型 还将研究酸中毒。 通过研究全动物酸碱状态和酸的改变 排泄，酶活性，孤立小管中的净酸化和 基底外侧质子扩展被阻塞时，pH恢复，我们希望 阐明ATPase活性与管状之间的关系 功能。