[Effect of chemotherapy on the nucleoside phosphate kinase activity in experimental tumors]

In animals with experimental transplantable tumors, an effective treatment with antitumor compounds brought about interrelated changes in nucleoside phosphate kinase activity. The decrease in thymidine phosphate kinase activity was as a rule matched by an increase in that of uridine phosphate kinase. Consequently, "thymidine kinase-uridine kinase" shunt responsible for thymidine-uridine interconversion was suggested, which is switched on when the homeostasis of tumor cells is disturbed. In treatment of tumor-bearing animals, the effective dosage of antitumor drugs was considerably decreased due to a combination of the said compounds (inhibiting nucleoside kinases) or with azauridine which inhibits uridine monophosphate synthesis from orotidine-5'-phosphate.