Effect of phenobarbital on the activity of RNA polymerase II during diethylnitrosamine-induced hepatocarcinogenesis in the rat.

The effects of dietary phenobarbital (PB) on RNA polymerase II (nucleoside triphosphate: RNA nucleotidyltransferase, EC 2. 7. 7. 6) in the liver of male Sprague-Dawley rats previously administered diethylnitrosamine (DENA) were studied. When a diet containing 0.05% phenobarbital was administered, the activity of DNA-dependent RNA polymerase II in the liver nuclei of rats was temporarily increased 1 and 2 weeks after the onset of feeding and expressed to be relatively higher afterwards, compared with the activity in rats fed the control diets.