PHENOBARBITAL AND METHYLCHOLANTHRENE STIMULATION OF RAT LIVER CHROMATIN TEMPLATE ACTIVITY

Both phenobarbital and 3-methylcholanthrene increase the activity of liver microsomal drug metabolizing enzymes, as discussed by Conney (1967). This increased enzyme activity is due to de novo protein synthesis, as indicated by the studies of Von der Decken and Hultin (1960), Gelboin and Sokoloff (1961), and Conney and Gilman (1963). Madix and Bresnick (1967) have shown that chromatin isolated at 7 and 16 hours after administration of the carcinogen 3-methylcholanthrene is a more effective template for in vitro RNA synthesis than chromatin from control animals. The results presented in the present report indicate that chromatin isolated from rat liver 12 hours after administration of phenobarbital or 3-methylcholanthrene is a more effective template for RNA synthesis when compared to controls, and that differences in template activity are abolished when basic proteins are removed from the chromatin preparations. © 1968.