EFFECT OF VANADATE IN ACUTE METABOLIC-ACIDOSIS

The effect of vanadate on urinary excretion of acid and electrolyte in dogs with hydrochloric acid (HCl)-induced acute metabolic acidosis wa s studied. Vanadate caused no changes in systemic and renal haemodynam ics, blood parameters and net acid excretion (NAE) in the control grou p. In the acute metabolic acidosis group, metabolic acidosis ger se al so had no effect on haemodymic parameters. Fractional excretion of bic arbonate was decreased, while NAE was markedly increased. Following va nadate treatment, acute acid-loaded animals showed an increase in mean arterial pressure (MAP), but a decreased glomerular filtration rate a nd effective renal plasma flow. These animals had reduced NAE compared to that seen with HCl alone. Thus, vanadate impaired the renal adapti ve responses to acute metabolic acidosis. The decreased NAE induced by vanadate might be caused by its known inhibitory effect on hydrogen-p otassium-adenosine triphosphatase (H-K-ATPase) and sodium-potassium-ad enosine triphosphatase (Na-K-ATPase), and by renal vasoconstriction.