REGULATION OF RENAL NA+/K+ ATPASE ACTIVITY

肾 NA /K ATP 酶活性的调节

• 批准号: 2139038
• 负责人: BARBARA M RAYSON
• 金额: $ 3.54万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-09-01 至 1994-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2139038
• 关键词: bioenergetics; biological transport; cell membrane; electrolyte balance; enzyme mechanism; fluorescence spectrometry; genetic transcription; genetic translation; histochemistry /cytochemistry; ion transport; kidney pharmacology; laboratory rat; membrane transport proteins; messenger RNA; nuclear magnetic resonance spectroscopy; ouabain; potassium; renal hypertension; renal tubular transport; sodium; sodium potassium exchanging ATPase

Chronic inhibition of Na=/K+ -ATPase activity in superfused rat kidney segments stimulates the synthesis of new active pump sites, a response which appears to be mediated by chronic changes in intracellular levels. Over the course of this response, intracellular Na+ and Ca2+ levels are elevated acutely, but over incubation intervals of 18 hours, the time required for the generation of new Na+/K+ -ATPase enzyme sites, both [Na+i] and [Ca+i] are restored to levels which are not different from controls. Similarly [K+i] levels, though acutely decreased by ouabain treatment are also restored to control levels over 18 hour incubation intervals. Thus the response constitutes an effective cellular "homeostatic response". A defect in this response occurs in suspensions of tubular segments prepared from the kidneys of Dahl salt-sensitive rats, a genetic model of volume expanded hypertension. No response is detectable. [Na+i] continues to rise over 18 hours of ouabain treatment. On the other hand an effective "homeostatic response" is demonstrable in suspensions of tubular segments prepared from the kidneys of Dahl salt-resistant rats, the genetic counterparts of the salt-sensitive animals. The first goal of this proposal is the localization of the defect exposed, within the cellular mechanism of the response. Rates of synthesis and degradation of Na+/K+ - ATPase will be measured in tubular suspensions prepared from the kidneys of both Dahl salt-sensitive and salt-resistant rats. Any defect exposed in the synthetic Na+/K+ -ATPase response, will then be pursued at both the transcriptional and translational level. The second goal of this proposal is to identify the ion species which contribute to the regulation of the rate of Na-K -ATPase synthesis. Changes in specific mRNA levels will be measured in response to a range of intracellular electrolyte manipulations in tubular suspensions from the kidneys of Sprague Dawley rats. Once the potential mediators of the response have been identified, the role played by their possible abnormal regulation in the "homeostatic response" defect in the kidneys of Dahl salt-sensitive rats, will be investigated. The localization of the defect in the response in Dahl salt-sensitive kidneys could well point to defects causal in volume expanded forms of human hypertension.

灌流大鼠肾脏Na ~+/K ~+ -ATP酶活性的慢性抑制 节段刺激新的活性泵位点的合成， 这似乎是由细胞内水平的慢性变化介导的。 在这种反应过程中，细胞内Na+和Ca 2+水平是 急性升高，但在18小时的潜伏期内， 所需的新的Na+/K+ -ATP酶酶位点的产生，两个[Na+i] 和[Ca+1]恢复到与对照无差异的水平。 类似地，[K+i]水平，虽然通过哇巴因治疗而急剧降低，但仍在升高。 在18小时的孵育间隔内也恢复到对照水平。 因此 该应答构成有效的细胞“稳态应答”。 这种反应的缺陷发生在管状段的悬浮液中 从达尔盐敏感大鼠的肾脏制备， 容积扩张性高血压 未检测到任何反应。 [Na+i]继续 18个小时的哇巴因治疗后 另一方面，有效 “稳态反应”在管状节段的悬浮液中是可证实的。 从达尔耐盐大鼠的肾脏中制备的基因， 盐敏感动物的对应物。 第一个目标是 建议是暴露的缺陷的定位，在细胞内， 反应的机制。 Na+/K+ -的合成和降解速率 ATP酶将在从以下动物的肾脏制备的管状悬浮液中测量： Dahl盐敏感和耐盐大鼠。 任何暴露在 合成的Na+/K+ -ATP酶反应，然后将在两个 转录和翻译水平。 本提案的第二个目标是 是确定有助于调节的离子种类， Na-K -ATPase合成速率。 特定mRNA水平的变化将是 对一系列细胞内电解质操作的反应 在Sprague道利大鼠肾脏的管状悬浮液中。 一旦 潜在的反应介质已经确定，所发挥的作用 通过它们在“稳态反应”缺陷中可能的异常调节， 在达尔盐敏感大鼠的肾脏中，将进行研究。 的 Dahl盐敏感肾反应缺陷的定位 可以很好地指出缺陷的因果关系，在体积扩大形式的人类 高血压