Renal Tubular Acidosis in Cadmium-Intoxicated Rats

Renal Tubular Acidosis in Cadmium-Intoxicated Rats

<P> Effect of cadmium (Cd) intoxication on renal acid-base regulation was studied in adult male Sprague-Dawley rats. Cd intoxication was induced by subcutaneous injections of CdCl<SUB>2 </SUB>at a dose of 2 mg Cd/kg/day for 3∼4 weeks. In Cd-intoxicated animals, arterial pH, PCO<SUB>2</SUB> and plasma bicarbonate concentration decreased, showing a metabolic acidosis. Urine pH and urinary bicarbonate excretion increased and titratable acid excretion decreased with no change in ammonium excretion. In renal cortical brush-border membrane vesicles derived from Cd-exposed animals, the Na<SUP>&#8290;</SUP>/H<SUP>&#8290;</SUP> antiporter activity was significantly attenuated. These results indicate that chronic exposures to Cd impair the proximal tubular mechanism for H<SUP>&#8290;</SUP> secretion (i.e., Na<SUP>&#8290;</SUP>/H<SUP>&#8290;</SUP> antiport), leading to a metabolic acidosis.