Activities of drug-metabolizing enzymes in isolated gamma-glutamyltranspeptidase positive preneoplastic hepatocytes from carcinogen treated rats.

Drug metabolizing enzyme activities were determined in isolated putatively preneoplastic, gamma-glutamyltranspeptidase (gamma-GT) positive hepatocytes from male Wistar rats fed 2-acetylaminofluorene (AAF). The cells were isolated by affinity binding to anti-gamma-GT antibody coated dishes, the resulting suspension contained 60-87% gamma-GT-positive cells. Cytochrome P-450 dependent metabolism of benzo[a]pyrene, aldrin and ethoxyresorufin was 43-54% lower than in the parent cell suspension, glucuronidation of 3-hydroxybenzo[a]pyrene (3-OH-BP) and hydrolysis of styrene oxide were increased 1.5- and 1.4-fold, respectively. The altered pattern of drug metabolizing enzyme activities in isolated gamma-GT-positive hepatocytes is consistent with the increase in resistance of preneoplastic liver cells to hepatotoxins.