Xenobiotic metabolism by cultured primary porcine hepatocytes

Considering the large yield of viable cells comparable to human liver, prim ary porcine hepatocytes offer a valuable resource for constructing a bioart ificial liver device. In this study, the ability of cultured primary porcin e hepatocytes to detoxify xenobiotics has been examined using various known substrates of cytochrome P450 isoenzymes and UDP-glucuronosyltransferases. Present investigation demonstrated the stability of the isoenzymes respons ible for the metabolism of diazepam in native state and stabilization of ot her isoenzymes, as judged by ethoxycoumarin o-dealkylase (ECOD), ethoxyreso rufin o-dealkylase (EROD), benzyloxyresorufin o-dealkylase (BROD), and pent oxyresorufin o-dealkylase (PROD) activities following induction in culture environment, for a period of 8 days. Resorufin O-dealkylase activities were found to be the most unstable and deteriorated within first 5 days in cult ure. These activities were restored following induction with 3-methylcholan threne (3-MC) or sodium phenobarbital (PB) to 20-fold of 1 activity for ERO D, and 60 and 174% of day 1 activity for PROD and BROD on day 8, respective ly. Metabolism of methoxyresorufin was most strikingly increased following induction with 3-MC to approximately 60-fold of day 1 activity, on day 8. U DP-glucuronosyltransferase-dependent glucuronidation of phenol red, however , stayed intact during the course of our study without induction. Our study indicated that porcine hepatocytes in vitro maintain many important liver- specific functions including detoxification (steady state and inducibility) .