Abstract

Chlorothiazide in dilute solution was administered by constant-speed infusion into one renal artery in each of thirteen dogs. In all dogs there occurred an increase in the excretory rates of chloride, sodium and water with a lesser increase in the excretory rate of potassium. In two dogs the response was limited to the kidney being infused. In the remaining dogs, the response was bilateral but greater in the infused than the control kidney.

It is concluded that chiorothiazide acts directly at an intrarenal site to exert its excretory effects. Since renal blood flow and glomerular filtration rate did not change, this site must be tubular in origin.