Expression and inducibility of drug-metabolizing enzymes in preneoplastic and neoplastic lesions of rat liver during nitrosamine-induced hepatocarcinogenesis

H. W. Kunz, A. Buchmann, M. Schwarz, R. Schmitt, Wolf D. Kuhlmann,
C. R. Wolf, F Oesch


Institute of Biochemistry, German Cancer Research Centre, D-6900 Heidelberg, FRG
Imperial Cancer Research Fund, Laboratory of Molecular Pharmacology and Drug Metabolism,
University Department of Biochemistry, Edinburgh, UK
Institute of Toxicology, University of Mainz, D-6500 Mainz, FRG

The expression, inducibility, and regulation of four different cytochrome (cyt.) P-450 isoenzymes (PB1, PB2, MC1, and MC2), NADPH-cytochrome P-450 reductase, the glutathione transferases (GSTs) B and C and microsomal epoxide hydrolase (mEHb) have been studied during nitrosamine-induced hepatocarcinogenesis using immunohistochemical techniques (immunoperoxidase method). The investigations revealed basic differences in the expression of the individual drug metabolizing enzymes in the course of neoplastic development.