Induction of propranolol metabolism in the Hep G2 human hepatoma cell line.
Metabolism of propranolol by the human hepatoma cell line Hep G2 was studied. Although metabolism qualitatively was similar to that in-vivo, the P450-mediated N-desisopropylation clearly predominated. Pretreatment of cells with 3-methylcholanthrene increased the activity of this pathway 14-fold, whereas phenobarbitone had no effect. This is similar to the pathway-selective inductive response observed for cigarette smoking in-vivo. As in-vivo, secondary metabolism of N-desisopropylpropranolol was extensive. This could, however, be completely blocked by 0.1 microM clorgyline, a potent MAO type A inhibitor. As in human liver microsomes, the stereochemistry of propranolol metabolism demonstrated a preference for the R(+)-enantiomer. These observations emphasize the usefulness of the Hep G2 cell line as a model of man.
Steiner
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A
Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston 29425.
Walle
U K
UK
Walle
T
T
D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism*; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology; D010084:Oxidation-Reduction; D011433:Propranolol / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D008996:Monoamine Oxidase Inhibitors; D011433:Propranolol