RNA synthesis and RNA polymerase activity in hepatic nuclei isolated from rats fed the carcinogen 2-acetylaminofluorene

Abstract

An assessment was made of the activity of RNA polymerase I and the capacity for RNA synthesis, under conditions optimized for RNA polymerase I activity, in hepatic nuclei isolated from rats fed a diet containing the hepatic carcinogen AAF. Animals were maintained on the carcinogenic diet for either 4, 7 or 14 days. RNA polymerase activity progressively increased with time on the carcinogenic diet. However, the capacity for RNA synthesis remained quite constant. These results are suggestive of a progressive inhibition of DNA template activity during the early stages of AAF-induced hepatocarcinogenesis. The “permanance” of the increase in polymerase activity was examined by switching carcinogen fed animals to a control diet for either 2 or 5 days prior to making an assessment of the above parameters.