Early effects of aldosterone on Na-K pump in rat cortical collecting tubules

Journal Article · Sun Jul 01 04:00:00 EDT 1990 · American Journal of Physiology; (USA)

OSTI ID:6530295

Fujii, Y; Takemoto, F; Katz, A I ^[1]

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1. Univ. of Chicago Pritzker School of Medicine, IL (USA)

Sustained exposure to aldosterone (Aldo) increases the abundance and activity of the Na-K pump in cortical collecting tubules (CCT). However, the onset and mechanism of the early interaction of Aldo with the CCT pump, especially in adrenal-intact animals, are unclear. We evaluated the short-term effects of the hormone on Na-K-adenosinetriphosphatase (ATPase) activity and on ouabain-sensitive 86Rb uptake, a measure of the transporting rate of the pump, in microdissected CCT from adrenal-intact rats. Incubation with Aldo (10(-8) M, 2 h) had no effect on Na-K-ATPase activity (Vmax), whereas it produced at least a twofold increase in 86Rb uptake. This effect was generated by physiological concentrations of the hormone (threshold 10(-10) M; apparent K1/2 approximately 10(-9) M), after a short lag of less than or equal to 30 min. Incubation with Aldo in the presence of amiloride or nystatin or in a Na-free medium (choline chloride) did not prevent the enhanced 86Rb uptake seen after Aldo alone; possible interpretations of these observations are discussed. We conclude that Aldo produces a rapid stimulation of pump function in CCT that precedes its induction of new pump synthesis; the physiological significance of this effect is suggested by its occurrence in tubules from adrenal-intact animals within the time frame and concentration range of the hormone's effects on electrolyte transport.

• OSTI ID: 6530295
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 259; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
ADRENAL HORMONES
ALDEHYDES
ALDOSTERONE
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
ANIMALS
ATP-ASE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BODY
CARBOHYDRATES
CARDIAC GLYCOSIDES
CARDIOTONICS
CARDIOVASCULAR AGENTS
CELL CONSTITUENTS
CELL MEMBRANES
CORTICOSTEROIDS
DAYS LIVING RADIOISOTOPES
DRUGS
ENZYME ACTIVITY
ENZYMES
GLYCOSIDES
HYDROLASES
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KETONES
KIDNEYS
KINETICS
MAMMALS
MEMBRANE TRANSPORT
MEMBRANES
MINERALOCORTICOIDS
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
OUABAIN
PHOSPHOHYDROLASES
POTASSIUM COMPOUNDS
PREGNANES
RADIOISOTOPES
RATS
REACTION KINETICS
RODENTS
RUBIDIUM 86
RUBIDIUM ISOTOPES
SODIUM COMPOUNDS
STEROIDS
STROPHANTHINS
TRACER TECHNIQUES
TUBULES
VERTEBRATES