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Research Article Free access | 10.1172/JCI105689
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
‡Dr. Katz was a Postdoctoral Trainee of the U. S. Public Health Service (AM 5015) and Fellow of the Connecticut Heart Association.
§Dr. Epstein is a Research Career Awardee, U. S. Public Health Service (K6-AM-21578).
Address requests for reprints to Dr. Franklin H. Epstein, Department of Internal Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, Conn. 06510.
*Received for publication 21 June 1967 and in revised form 20 July 1967.
This work was presented in part at the national meeting of The American Society for Clinical Investigation, 30 April 1967, and was aided by grants HE 00834 and AM 5015 from the U. S. Public Health Service.
Find articles by Katz, A. in: JCI | PubMed | Google Scholar
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
‡Dr. Katz was a Postdoctoral Trainee of the U. S. Public Health Service (AM 5015) and Fellow of the Connecticut Heart Association.
§Dr. Epstein is a Research Career Awardee, U. S. Public Health Service (K6-AM-21578).
Address requests for reprints to Dr. Franklin H. Epstein, Department of Internal Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, Conn. 06510.
*Received for publication 21 June 1967 and in revised form 20 July 1967.
This work was presented in part at the national meeting of The American Society for Clinical Investigation, 30 April 1967, and was aided by grants HE 00834 and AM 5015 from the U. S. Public Health Service.
Find articles by Epstein, F. in: JCI | PubMed | Google Scholar
Published December 1, 1967 - More info
In order to evaluate the possible role of sodium- and potassium-activated adenosine triphosphatase in the active transport of sodium by the renal tubules, we examined the effect of large changes in the tubular reabsorptive load of sodium on the Na-K-ATPase activity of rat kidney homogenates. Glomerular filtration and tubular reabsorption of sodium per gram of kidney tissue increased progressively after contralateral uninephrectomy. This was paralleled by an increase in Na-K-ATPase per milligram of protein in a microsomal fraction of kidney cortex. The importance of this change is underlined by the absence of simultaneous increases in other microsomal enzymes such as glucose-6-phosphatase and Mg++-dependent ATPase, or in succinic dehydrogenase or glutaminase. Similar increases in Na-K-ATPase were observed when the net tubular reabsorption of sodium was increased by feeding the animals a high-protein diet or after injection of methylprednisolone. On the other hand, Na-K-ATPase was lowered when tubular transport of sodium was reduced by bilateral adrenalectomy. The results of these experiments show that renal Na-K-ATPase changes in an adaptive way when renal reabsorption of sodium is chronically increased or diminished and support the hypothesis that this enzyme system is involved in the process by which sodium is actively transported across the renal tubule.