Organophosphate detoxification related to induced hepatic microsomal enzymes of chickens.

Detoxification of the organophosphate malathion in its activated form (malaoxon) was increased in livers of chickens given microsomal enzyme inducers (beta-naphthoflavone, 3-methylcholanthrene, butylated hydroxytoluene (BHT), or polychlorinated biphenyls). Positive correlations between inducer and microsomal enzyme activity were demonstrated for beta-naphthoflavone with demethylation of p-nitroanisole and for 3-methylcholanthrene and for BHT with cytochrome P450/448 and cytochrome b5. Malaoxon detoxification decreased in correlation with decreases in quantities of cytochrome P450/448 in birds fed a low-protein diet. Prediction of malaoxon detoxification was aided by using enzyme activities as dependent variables in the regression model, although only in birds given BHT were all of the 5 enzymes necessary for providing the best predictive model.