Ligand-dependent maintenance of ethanol-inducible cytochrome P-450 in primary rat hepatocyte cell cultures.

Administration of ethanol, dimethylsulphoxide, 2-propanol or imidazole to rats caused 2-7-fold increases in the level of hepatic ethanol-inducible cytochrome P-450 (P-450j), without any concomitant enhancement of corresponding mRNA. All the compounds were able to stabilize P-450j in hepatocyte cultures for at least three days, whereas P-450j mRNA rapidly disappeared from the cultures. A correlation was reached between the concentration of Me2SO, ethanol and 2-propanol necessary to maintain P-450j in the cell cultures and their binding affinities to the enzyme. It is suggested that the ligand-bound form of P-450j in the hepatocytes is protected from degradation.