Influence of age on in vitro effect of cadmium on rat liver cytochrome P-450 concentration and monooxygenases activity.

Cadmium++ added in vitro destroys rat liver cytochrome P-450 (cyt. P-450) with increasing age by 25-50%. Ethylmorphine N-demethylation is inhibited only in rats 30-days old and thereafter. Ethoxycoumarin 0-deethylation is inhibited even in newborn rats, and the maximal inhibition appears to increase with age. It is concluded that in all age groups cadmium resistant cyt. P-450 subspecies are present. Ethoxycoumarin 0-deethylase activity possibly indicates the cadmium sensitive P-450 fraction.