Liver drug-metabolizing enzyme activities

Table I. Drug-metabolizing enzyme activities in liver of animals.

Nakajima T, Sato A. 1979. Enhanced activity of liver drug-metabolizing enzymes for aromatic and chlorinated hydrocarbons following food deprivation. Toxicol AppI Pharmacol 50 549-556. 

The test article is not metabolized by liver microsomes, or hepato-cytes This is indicated by the lack of either metabolite formation or parent disappearance in Studies 1 and 2. Hepatic metabolism is not involved in the metabolic clearance of the compound. There should be no concern with coadministered drugs that can alter drug-metabolizing enzyme activities. 

The activity of CYP3A isoenzymes in the human fetal liver is similar to that seen in adult liver microsomes. The fetal activity for CYP3A7 isoenzyme is unusual as most other fetal isoenzymes of CYP450 exhibit 5 to 40% of fhe adulf isoenzymes. Fetal and neonatal drug-metabolizing enzyme activities may differ from those in the adult. 

The effects on the liver are less pronounced. Changes in hepatic drug metabolizing enzyme activity have been demonstrated in rodents after parenteral and oral Cd treatment, although both inhibition (Hadley et al. 1974 Schnell et al. 1976, 1979) and potentiation (Johnston et al. 1975) have been reported. In the present study in females of the highest dose group a reduction in AH-activity and Cytochrome P450 concentration was observed. 

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