The Stimulatory Effect of 3-methylcholanthrene on Benzpyrene Hydroxylase Activity in Several Rat Tissues: Inhibition by Actinomycin D and Puromycin.

The presence of benzpyrene hydroxylase activity in the small intestine, lung, and kidney of the normal rat has been shown by quantitative assay and compared with the level of activity in the liver. The intraperitoneal injection of methylcholanthrene in creased the level of activity found in each of the four tissues examined. The stimu lation by methylcholanthrene was inhibited by the simultaneous administration of puromycin or actinomycin D, suggesting that the changes in enzyme level are de pendent on protein and RNA synthesis in these tissues. Possible implications to a theory of carcinogenesis are discussed.