Changes in the Quantity and Activity of Cytochrome P‐450 Isozymes in Primary Cultured Rat Hepatocytes

Hepatocytes from male Spragne‐Dawley rats pretreated with a cytochrome P‐450 inducer, 3‐methoxy‐4‐aminoazobenzene (3‐MeO‐AAB), 3‐methylcholanthrene (MC) or phenobarbital (PB), were cultured in vitro, and changes in the quantity and activity of microsomal cytochrome P‐450 isozymes in the cells were determined by means of immunochemical methods and a bacterial mutation test, respectively. The results of enzyme‐linked immunosorbent assay using monoclonal antibodies against rat P‐450 isozymes ‐ test using Salmonella typhimurium TA 98 and carcinogenic aromatic amines. These results indicate that microsomal cytochrome P‐450c in primary cultured rat hepatocytes is more stable in culture, in terms of both quantity and activity, than cytochrome P‐450d and P‐450b/e.