Benzo[e]pyrene metabolism in rat liver microsomes: dependence of the metabolite profile on the pretreatment of rats with various monooxygenase inducers.

Benzo[r]pyrene (B[e]P) is metabolized by liver microsomes of untreated rats to trans-4,5-dihydroxy-4,5-dihydrobenzo(e)pyrene and 1- as well as 3-hydroxybenzo[e]pyrene as shown by g.l.c. and mass spectrometry of their trimethylsilyl ethers. After pretreatment of the rats with various monooxygenase inducers oxidation at the 9/10-position was also observed. In addition, secondary oxidation to dihydrodiolepoxides and the formation of a tetrol, tentatively identified as 4,5,9,10-tetrahydroxy-4,5,9,10-tetrahydrobenzo[e]pyrene was detected after incubation of B[e]P with liver microsomes of rats treated with polycyclic aromatic hydrocarbons. However, no formation of the supposed ultimate carcinogen, the 9,10-dihydroxy-11,12-epoxy-9,10,11,12-tetrahydrobenzo[e]pyrene could be observed after any of the pretreatments.