EFFECT OF BUCLADESINE SODIUM ON THE PLASMA-CONCENTRATIONS AND URINARY-EXCRETION OF PURINE-BASES AND URIDINE

To examine whether bucladesine sodium affects the plasma concentration s of purine bases (hypoxanthine, xanthine, and uric acid) and uridine, 100 mt of physiological saline containing bucladesine sodium (6 mg/kg weight) was administered intravenously to eight healthy subjects for 1 hour after overnight fast except for water. Blood was drawn 30 minut es before, and 30 minutes and 1 hour after the beginning of the infusi on, and 1-hour urine was collected before and after the beginning of t he infusion. Two weeks later, 100 mt of only physiological saline was administered under the same protocol. Bucladesine sodium decreased the plasma concentrations of hypoxanthine by 36% and by 37%, and of xanth ine by 16% and 33%, and of uridine by 17% and 30%, 30 minutes and 1 ho ur after the beginning of the infusion, respectively, and increased th e urinary excretion of hypoxanthine and uric acid by 140% and 30%, res pectively, after the beginning of the infusion. However, it did not af fect the plasma concentration of uric acid or the urinary excretion of xanthine, and the urinary excretion of uridine was less than 0.2 mu m ol/h before or after bucladesine sodium infusion. On the other hand, p hysiological saline alone did not affect any of the values described. These results suggest that bucladesine sodium acts on the secretory pr ocess of the renal transport of hypoxanthine, resulting in the increas ed urinary excretion of hypoxanthine, and further suggest that buclade sine sodium enhances the uptake of uridine in plasma to liver cells. C opyright (C) 1998 by W.B. Saunders Company.