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pubmed:abstractText |
The rates of benzo[a]pyrene metabolism were stimulated markedly by micromolar quantities of hematin when assayed with either fetal or maternal extrahepatic tissue parparations (9,000 g supernatant fractions) from rats, rabbits and humans. Enzymatic induction was accompanied by either decreases in the magnitude of hematin stimulation or hematin-mediated inhibition of monooxygenase activities. Additions of 7,8-benzoflavone (BF) resulted in the inhibition of reaction rates in most experiments. With either fetal or maternal hepatic preparations from untreated rabbits, however, BF stimulated enzymatic activities; the greatest simulation occurred in fetal rabbit liver (10-fold). Nevertheless, inducer pretreatment was associated with inhibitory of BF on activities in hepatic homogenates.
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