Renal memory after potassium adaptation: role of Na+-K+-ATPase.
The present study was designed to explore the time course of the resolution of enhanced Na+-K+-ATPase activity in the cortical collecting tubule (CCT) and the parallel changes in renal K excretion that are characteristic of potassium adaptation. Potassium-adapted male Sprague-Dawley rats manifested an enhanced kaliuretic response to an acute intravenous load of KCl and a doubling of Na+-K+-ATPase activity in the CCT. Withdrawal of dietary K loading from these adapted rats was associated with a gradual resolution of these adaptive biochemical (t1/2 of Na+-K+-ATPase return to base line 48 h) and excretory changes. During this resolution phase, however, a temporal discrepancy was uncovered between the change in dietary K and the slower changes in enzyme activity and renal K excretion with a persistence of the enhanced kaliuresis leading to a negative K balance. We conclude that the slow inactivation, after withdrawal of K loading, of the increased membrane transport proteins of K adaptation, will manifest as a renal memory of the antecedent excretory requirements.
Mujais
S K
SK
Department of Medicine, Northwestern University Medical School, Chicago, Illinois.
D000064:Acclimatization; D000818:Animals; D004032:Diet; D007668:Kidney / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D008297:Male; D011188:Potassium / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D000254:Sodium-Potassium-Exchanging ATPase / Q000502:physiology*
D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium