Oxygen requirement of renal Na-K-ATPase-dependent sodium reabsorption.
The oxygen requirement of the Na-K-ATPase-dependent sodium transport system was examined in anesthetized dogs infused with 15% mannitol-Ringer solutions at a rate of 35 ml/min. Because of renal vasodilatation and abolished autoregulation, filtered sodium (FNa) could be varied over a wide range by progressive aortic constriction. Sodium reabsorption (RNa) and renal oxygen consumption (RVO2) varied in proportion to FNa (r greater than 0.9). Ouabain, which inhibits Na-K-ATPases, reduced RVO2 by 45 +/- 6%. During subsequent aortic constriction, the ratio delta RNa/delta FNa averaged 0.45 (glomerulotubular balance) (r less than 0.9), whereas RVO2 was not significantly altered. Comparisons of deltaRNa/deltaFNa before and after ouabain administration, indicate that about half of an increase in sodium delivery to the distal nephron is reabsorbed by the Na-K-ATPase-dependent sodium transport system and that deltaRNa/deltaRVO2 (Na/O2 ratio) of this system averages 14.5 +/- 1.3. This Na/O2 ratio corresponds to 2.4 sodium ions transported per ATP dephosphorylated as found in other tissues.
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D003250:Constriction; D004285:Dogs; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D007668:Kidney / Q000378:metabolism* / Q000502:physiology; D007773:Lactates / Q000378:metabolism; D008297:Male; D008433:Mathematics; D010042:Ouabain / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects; D011188:Potassium / Q000494:pharmacology; D012077:Renal Artery; D012964:Sodium / Q000378:metabolism* / Q000494:pharmacology
D007773:Lactates; D010042:Ouabain; D012964:Sodium; D000251:Adenosine Triphosphatases; D011188:Potassium