Rate Of Bicarbonate Reabsorption Research Articles

EFFECT OF CARBONIC ANHYDRASE INHIBITION ON PROXIMAL TUBULAR BICARBONATE REABSORPTION.

Samples of fluid from the proximal tubule were collected for the measurement of pH and bicarbonate concentration before and after the administration of acetazolamide (Diamox). Samples collected before acetazolamide were consistently more acid than plasma with the most acid samples coming from the more distal portion of the proximal tubule. After the intravenous administration of acetazolamide, the pH and bicarbonate concentration were consistently higher than in plasma. Bicarbonate concentrations as high as 2.8 times that in plasma were observed. The rise in proximal tubular fluid bicarbonate concentration after acetazolamide is presumably due to a reduction in the rate of bicarbonate reabsorption out of proportion to any impairment in proximal tubular fluid volume reduction.

The effect of acute elevation of the plasma chloride concentration on the renal excretion of bicarbonate during acute respiratory acidosis.

It has been postulated recently that renal bicarbonate reabsorption is entirely dependent on the exchange of hydrogen ions, derived from the dissociation of carbonic acid within the cells of the renal tubule, for the fixed base of filtered bicarbonate in the tubular urine (1-3). According to this theory, an elevation of the CO2 tension of the extracellular fluid results in an increase in the rate of bicarbonate reabsorption because it leads to an increase in the rate of hydrogen ion