Polychlorinated Biphenyls: A New Type of Inducer of Cytochrome P-448 in the Liver

摘要: Abstract The CO-difference spectrum of microsomes from rats treated with the polychlorinated biphenyls mixture, Aroclor 1254, has an absorption maximum at 448 nm. With ethylisocyananide as ligand for reduced microsomes, 1254 treatment causes a shift in 455-nm peak to 453 nm and increases ratio absorbance 455 that 430 0.53, obtained untreated rats, 1.24. These findings are similar those seen polycyclic hydrocarbon, 3-methylcholanthrene, but differ characterize cytochrome P-450 control or phenobarbital-treated rats. results tripling P-448 content 10-fold increase benzo-[a]pyrene hydroxylation. However—unlike like phenobarbital type inducing agents—Aroclor significant enhancement ethylmorphine N-demethylase. data suggest 1254-induced may be catalytically different 3-methylcholanthrene-induced hemoprotein(s) induced by mixture cytochromes exhibiting catalytic properties both cytochromes.