Role of Carbonic Anhydrase in Anion Excretion in the Alligator

Abstract

The influence of carbonic anhydrase inhibition on the excretion of exogenous sulfate, phosphate, bicarbonate and chloride was studied by injecting large amounts of salts both with and without Diamox. Renal carbonic anhydrase is necessary for the conservation of chloride by the alligator. Diamox had no effect on the excretion of sulfate or phosphate, therefore it is unlikely that carbonic anhydrase is normally involved in excretion of these ions. Although urinary CO₂ after NaHCO₃ injection was decreased by Diamox, it is improbable that this represents any influence on the excretion of filtered bicarbonate. It is postulated that this decrease is due to the inhibition of tubular production of CO₂. Carbonic anhydrase inhibition leads to a slight but probably significant increase in K excretion.