Effect of 5-Fluorouracil on Thymidine Phosphorylase Activity in Model Experiment.

Variations in thymidine phosphorylase activity in rat liver were studied in 1, 3, 6, 12, and 24 h after intraperitoneal bolus injection of 5-fluorouracil. Enzyme activity was measured by HPLC. A 2-fold decrease in enzyme activity was observed 3 h after 5-fluorouracil administration and persisted for 12 h.