Cadmium administration and hepatic drug metabolizing enzyme system: effect of pretreatment with phenobarbital and 3-methyl cholanthrene.

A single dose of cadmium sulphate (2 mg/kg, ip) produced variable effects on the components of hepatic microsomal enzyme system in untreated, phenobarbital and 3-methyl cholanthrene pretreated rats. Measurements of the activities of these components showed that phenobarbital pretreatment prevented the decrease in the specific activity of benzphetamine demethylase, as well as decrease in the contents of cytochrome P-450 and phosphatidyl choline seen in rats given cadmium alone. In contrast, prior administration of 3-methyl cholanthrene did not protect against the inhibitory effect of the metal on cytochrome P-450 and phospholipid components. However, the dose of cadmium used in this study did not appear to have any significant effect on the activities of cytochrome P-450 reductase and aniline hydroxylase.