Inhibition of Urine Citrate Excretion

We have previously observed that the urinary excretion of citrate is reduced to low levels in rats treated with the carbonic anhydrase inhibitor, acetazoleamide (Diamox®g) (1). This first experiment was prompted by the fact that the elevated serum chloride and decreased serum bicar-. bonate concentrations, and the fixation of the urine pH at approximately 7 or above following administration of an agent which inhibits carbonic anhydrase activity resembles the findings in patients with congenital renal tubular acidosis. In a study of an infant with this syndrome we found that the urinary excretion of citrate was too low to be measured (1). The absence of citrate in the urine of this patient persisted even after the hyperchloremia and acidosis were corrected by administration of 40 mM of sodium lactate daily and the urine pH was raised to about 8.0. This is in contrast to the findings in normal subjects in whom the renal excretion of citrate increases when the urine is made alkaline by administration of sodium or potassium bicarbonate or the sodium and potassium salts of organic acids (2). It has also