Kidney in potassium depletion. I. Na/sup +/-K/sup +/-ATPase activity and (/sup 3/H)ouabain binding in MCT

Journal Article · Sun Mar 01 04:00:00 EST 1987 · Am. J. Physiol.; (United States)

OSTI ID:5956924

Hayashi, M; Katz, A I

The effect of potassium depletion on renal Na/sup +/K/sup +/-ATPase was studied in rats. K depletion produced a striking, time-dependent increase in Na/sup +/-K/sup +/-ATPase activity of the outer medullary collecting tubules (inner stripe; MCT/sub is/). After 3 wk on the K-free diet, when the urine was almost potassium-free, Na/sup +/-K/sup +/-ATPase activity in MCT/sub is/ was over fourfold higher than in control animals. Repletion of potassium restored enzyme activity to base line within 7 days which corresponds to the catabolic rate of the renal enzyme, suggesting the cessation of enhanced synthesis that took place during K deprivation. Changes in Na/sup +/-K/sup +/-ATPase activity and aldosterone levels during both K depletion and repletion occurred in opposite directions and were therefore independent of each other. (/sup 3/H)Ouabain binding to intact MCT/sub is/, reflecting the number of pump sites on the basolateral membrane, was similar in K-depleted and control animals; in contrast, tubule permeabilization that exposes additional pump units to the ligand, unmasked a nearly fourfold increase in (/sup 3/H)ouabain binding in K-depleted rats, comparable to the increment in Na/sup +/-K/sup +/-ATPase activity. These results show that K depletion leads to a marked increase in Na/sup +/-K/sup +/-ATPase activity of MCT/sub is/, and suggest that the new enzyme units are located at a ouabain-inaccessible site in the intact tubule, i.e., either in an intracellular compartment or at the luminal membrane, where they may be involved in potassium reabsorption.

• Research Organization: Univ. of Chicago, IL
• OSTI ID: 5956924
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States) Vol. 252:3; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
ADRENAL HORMONES
ALDEHYDES
ALDOSTERONE
ALKALI METAL COMPOUNDS
ATP-ASE
BIOCHEMISTRY
BODY
CARBOHYDRATES
CARDIAC GLYCOSIDES
CARDIOTONICS
CARDIOVASCULAR AGENTS
CATIONS
CHARGED PARTICLES
CHEMISTRY
CLEARANCE
CONFIGURATION INTERACTION
CORTICOSTEROIDS
DRUGS
ENZYME ACTIVITY
ENZYMES
EXCRETION
GLYCOSIDES
HYDROLASES
HYDROXY COMPOUNDS
IONS
KETONES
KIDNEYS
LABELLED COMPOUNDS
MINERALOCORTICOIDS
ORGANIC COMPOUNDS
ORGANS
OUABAIN
PHOSPHOHYDROLASES
POTASSIUM COMPOUNDS
PREGNANES
SODIUM COMPOUNDS
STEROIDS
STROPHANTHINS
TRITIUM COMPOUNDS
TUBULES