[Tegafur and 5-FU concentrations in cancerous and normal tissues in nude mice after oral administration of UFT].

Tegafur and 5-fluorouracil (5-FU) concentrations in blood, tumor, kidney and liver tissues of nude mice implanted with human urogenital carcinoma were determined after oral administration of UFT. The results were as follows: The concentration of tegafur in serum and other tissues rose quickly reading to the peak levels by 15 minutes after administration of UFT, then decreasing gradually. The concentration of 5-FU in serum, liver and kidney showed similar changes, but concentration of tumor tissues were maintained high until 2 hours after administration. These results suggest that coadministration of uracil with tegafur increase the antitumor activity of tegafur.