Title: Modulation of monooxygenase activities by hematin and 7,8-benzoflavone in fetal tissues of rats, rabbits, and humans.

Authors: Omiecinski, C J; Chao, S T; Juchau, M R

Published In Dev Pharmacol Ther, (1980)

Abstract: 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.

PubMed ID: 7438968

MeSH Terms: Adrenal Glands/enzymology; Animals; Benzoflavones/pharmacology*; Cytochrome P-450 Enzyme System/analysis; Enzyme Induction; Female; Fetus/enzymology*; Flavonoids/pharmacology*; Heme/analogs & derivatives*; Hemin/pharmacology*; Humans; Liver/enzymology; Oxygenases/biosynthesis; Oxygenases/metabolism*; Pregnancy; Rabbits; Rats