INDUCTION OF HEPATIC MIXED-FUNCTION OXIDASES IN TROUT BY POLYCHLORINATED BIPHENYLS AND BUTYLATED MONOCHLORODIPHENYL ETHERS

Brook trout (Salvelinus fontinalis) were fed either a polychlorinated biphenyl (PCB) (Aroclor 1254) or a replacement material based on butylated monochlorodiphenyl ethers (formerly Dow Chemical Co. XFS-4169L, now sold as Dielectric Fluid C4) over a 15-day period to yield whole body concentrations (assuming complete retention of dose fed) of 200 μg/g, and the induction of hepatic mixed function oxidase (MFO) enzymes was studied. Concentrations of microsomal protein and cytochrome P-450 were significantly higher in fish fed Aroclor 1254 than in controls, and O-de-ethylase activity was increased fourfold. Trout fed XFS-4169L showed only slight increases over control values in most components of the MFO system; only the cytochrome P-450 concentration was significantly increased and O-deethylase activity was unchanged. About 25% of the Aroclor 1254 fed was deposited in fillets of the trout; there was no obvious selectivity of components. Much less XFS-4169L was deposited; the components most efficiently retained represented only about 8% of the dose fed, and one of its major components, 4-sec-butyl-4′-chlorodiphenyl ether, was scarcely retained at all. © 1979.