Stabilization of cytochrome P4502E1 protein by ethanol in primary hamster hepatocyte cultures

We report the effect of ethanol on monooxygenase activities in primary hams ter hepatocyte cultures maintained on collagen-coated dishes. The addition of 50 mM ethanol to cell cultures both from control and ethanol pretreated animals almost completely maintained, at least for 72 hr, the P4502E1-depen dent aniline hydroxylase (AnH) activity and the 2E1 immunodetectable apopro tein content at the levels of the corresponding I-hr plated hepatocytes. On the contrary, other P450-dependent monooxygenase activities, as assayed by testosterone hydroxylases, kept decreasing falling-after 72 hr of culture- to the levels of the l-hr plated hepatocytes. In both cases, in the absence of ethanol, a rapid decline of AnH activities and 2E1 apoprotein contents were also observed, attaining undetectable levels at 72 hr. The hybridizabl e 2E1 mRNA also rapidly declined in both cultures, but such decline was not significantly altered by the presence of 50 mM ethanol in the culture medi um. Furthermore, we show that P4502E1 in the liver possesses a rapid degrad ation phase with a half-life of about 6 hr. Thus, in the hamster, P4502E1 a ppears regulated at post-translational level, as in rat, probably by a prot ein stabilization mechanism. (C) 2000 Elsevier Science Ltd. All rights rese rved.