The aim of this work is the inhibition of pyrimidine catabolism in mammals, so that physiologically effective levels in circulating thymidine may be maintained. Dihydropyrimidine dehydrogenase was purified from rat and hamster livers, and various 5-substituted pyrimidines were tested as substrates. 5-Cyanouracil was reduced vigorously by enzyme from hamsters but only weakly by enzyme from rats; other analogs did not show this marked species difference. When 5-cyanouracil and uracil were tested together with the rat enzyme, the former blocked almost completely the reduction of uracil, which suggests that it is a good candidate for in vivo studies.

1

Supported by American Cancer Society grant T-357 and Faculty Research Associate Award PR-40 (P. A. M.), and USPHS training grant AI-69 and awards 5-K3-AI-7021 (G. A. G.) and 1-F1-GM-33650 (M. T. D.).

This content is only available via PDF.
©1969 American Association for Cancer Research.
1969
Cancer Research, Inc.