dUTP pyrophosphatase and uracil-DNA glycosylase in rat liver and hepatomas

1. 1. The activity of dUTP pyrophosphatase (dUTPase) was similar in rat liver and hepatomas of slow or moderate growth rate but was increased several fold in three rapidly growing hepatomas. 2. 2. There was an approx three-fold increase in the activity of uracil-DNA glycosylase in Morris hepatoma 7800 but there was little change in activity in other hepatomas that were examined. 3. 3. The activities of dUTPase and uracil-DNA glycosylase were not significantly affected by two diets that may be promotional for hepatocarcinogenesis, a high orotate diet and an arginine-deficient diet.