Activation and detoxification of 1,8-dinitropyrene by mammalian hepatic fractions in the Salmonella mutagenicity assay

2To whom correspondence should be addressed 1,8-Dinitropyrene (DNP) is a potent, direct-acting mutagen to Salmonella typhimurium TA98 due to activation by bacterial metabolism. We have studied the effects of unindueed and Arodor—induced rodent liver post-mitochondrial supernatant (S9), microsomes or cytosolic preparations on its activity. With the plate incorporation protocol, the reported S9-mediated inhibition of mutagenicity was confirmed and shown to be greater after induction when equivalent levels of protein were plated. Cytosol increased mutagenicity considerably whereas the inhibitory effect of S9 could be attributed to the microsomal fraction. The activating and detoxifying capacities of the various hepatic fractions derived from male Sprague-Dawley rats and Jemale BALB/c mice were similar. In the absence of hepatic preparations, DN