Adaptation of inner medullary collecting duct vacuolar H-adenosine triphosphatase to chronic acid or alkali loads in the rat

Exp Nephrol. 1994 May-Jun;2(3):171-5.

Abstract

Acidosis increases and alkalosis decreases proton secretion in the inner medullary collecting duct (IMCD). We examined the mechanism of this adaptation by studying the immunocytochemical distribution of the vacuolar H-adenosine triphosphatase (ATPase) in the IMCD from rats subjected to acid or alkali loads for a mean duration of 4 and 9 days. For immunocytochemical staining, a monoclonal antibody to the 31-kD subunit of the bovine kidney vacuolar H-ATPase was used. Intercalated cells were present only in the initial IMCD, and the principal cells and IMCD cells showed no appreciable H-ATPase staining under any experimental conditions. We found significant adaptive changes in the distribution of H-ATPase in the intercalated cells of the IMCD. H-ATPase staining in acid-loaded rats shifted from cytoplasmic vesicles to apical plasma membrane, whereas in alkali-loaded rats cytoplasmic vesicular staining was enhanced and staining of plasma membrane disappeared. These adaptive changes were most prominent on day 4 of acid-loaded and days 4 and 9 of alkali-loaded rats. Our results indicate that translocation of the H-ATPase pump between cytoplasmic vesicles and apical plasma membrane of the intercalated cells is an important mechanism is adaptation of the IMCD to chronic acid base perturbations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acidosis / physiopathology*
  • Adaptation, Physiological*
  • Alkalosis / physiopathology*
  • Ammonium Chloride / administration & dosage
  • Animals
  • Hydrogen-Ion Concentration
  • Kidney Medulla
  • Kidney Tubules, Collecting / metabolism*
  • Kidney Tubules, Collecting / physiology
  • Male
  • Proton-Translocating ATPases / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Sodium Bicarbonate / administration & dosage
  • Vacuoles / enzymology*

Substances

  • Ammonium Chloride
  • Sodium Bicarbonate
  • Proton-Translocating ATPases