Induction of drug metabolizing enzymes in the liver of rats infested with Fasciola hepatica.

Adult, male rats were infected with 20 metacercariae of Fasciola hepatica given orally, other rats were left untreated. Five weeks after infestation, some animals received phenobarbitone, 3-methylcholanthrene, beta-naphthoflavone or Arochlor 1254, to induce liver drug metabolizing enzymes. Fascioliasis provoked decreases in aminopyrine N-demethylase, aniline hydroxylase, the mutagenic activity of cyclophosphamide and cytochrome P-450 concentration in untreated or phenobarbitone or Arochlor pretreated rats. In contrast, cytochrome b5, NADPH cytochrome c reductase, ethyoxycoumarin O-deethylase and the enzymatic activation of ethidium bromide were not affected by fascioliasis whatever pretreatment was given. Fascioliasis decreased liver drug metabolizing enzymes which were specifically induced by both phenobarbitone and Arochlor, this could be due to either the specific action of toxic excretions of flukes or to the particular localization of tissue damage within the liver lobule.