Metabolism of phenanthridine to phenanthridone by rat lung and liver microsomes after induction with benzo[a]pyrene and aroclor

The comparative metabolism of phenanthridine (3,4-benzoquinoline) by rat lung and liver microsomes has been investigated. The array of metabolites produced by induced lung and liver are qualitatively similar. Phenanthridone has been identified as a phenanthridine metabolite produced by induced rat liver and lung. Phenanthridone is directly mutagenic in Salmonella tester strain TA-98 while phenanthridine is not. Although phenanthridone is more mutagenic than phenanthridine after incubation with rat liver 9000g supernatant fraction, it is less cytotoxic to Chinese hamster ovary cells in vitro.