Aspects of the inhibition of RNA synthesis by ethionine in rat liver

Nine hours after ethionine administration, an inhibition of RNA synthesis in vivo is detectable (about 80%). In vitro, purified nuclei have a decreased capacity for incorporating labeled precursor into acid-insoluble material, and both RNA polymerase I + III and RNA polymerase II activities are inhibited, thus confirming the effects of ethionine on RNA synthesis (for a review, see Farber, E. (1971) Annu. Rev. Pharmacol.11, 71–96). It is further reported that solubilized RNA polymerases from liver nuclei of ethionine-treated rats have decreased activities with respect to polymerases from control animals. Chromatin but not deproteinized chromatin from livers of treated rats had a reduced template activity when assayed with partially purified RNA polymerase II from normal rat liver.