Renal excretion of ascorbic acid by dogs

Abstract

The renal excretion of ascorbic acid was evaluated in dogs by clearance experiments and stop-flow analyses. After stimulation of the distal sodium-potassium exchange mechanism with deoxycorticosterone acetate, clearance experiments revealed ascorbic acid-to-creatinine clearance ratios as high as 1.54. Stop-flow analyses revealed a distal secretory peak in the area of sodium-potassium exchange with U/P-to-U/P ratios as high as 1.3. These experiments demonstrate that secretion of ascorbic acid occurs in the distal tubule. Linkage with the distal sodium-potassium exchange and an effect of urine pH on tubular handling of ascorbic acid are postulated.