RT Journal Article SR Electronic T1 Drug Metabolizing Capacity of Cryopreserved Human, Rat, and Mouse Liver Parenchymal Cells in Suspension JF Drug Metabolism and Disposition JO Drug Metab Dispos FD American Society for Pharmacology and Experimental Therapeutics SP 1415 OP 1422 VO 27 IS 12 A1 Steinberg, Pablo A1 Fischer, Thomas A1 Kiulies, Sandra A1 Biefang, Katja A1 Platt, Karl-Ludwig A1 Oesch, Franz A1 Böttger, Thomas A1 Bulitta, Clemens A1 Kempf, Peter A1 Hengstler, Jan YR 1999 UL http://dmd.aspetjournals.org/content/27/12/1415.abstract AB The phase I and phase II drug-metabolizing capacity of freshly isolated and cryopreserved parenchymal cells (PC) from human, rat, and mouse liver held in suspension at 37°C for up to 120 min after thawing was compared. Although 7-ethoxycoumarin-O-deethylase activity was strongly reduced in freshly isolated as well as in cryopreserved PC from human, rat, and mouse liver after 120 min, 7-ethoxyresorufin-O-deethylase activity as well as the profile and formation rates of hydroxylated testosterone metabolites in general remained constant throughout the 2-h incubation period in cryopreserved PC from all three species and was similar to that measured in freshly isolated PC. The activity of glutathioneS-transferase (GST) and that of UDP- glucuronosyltransferase (UDP-GT) toward 4-methylumbelliferone significantly decreased, whereas the activities of UDP-GT activity toward 4-hydroxybiphenyl and sulfotransferase in cryopreserved human PC were similar to those measured in freshly isolated PC. The activities of GST, UDP-GT toward 4-methylumbelliferone, and sulfotransferase in cryopreserved rat PC showed a significant decrease when compared with the activities in freshly isolated PC. The phase II enzyme activities in cryopreserved mouse PC proved to be far more stable, being similar to the activities of freshly isolated mouse PC at all four time points measured with the exception of GST, which showed a decay from t = 60 min onward. In conclusion, phase I drug-metabolizing enzyme activities in cryopreserved human, rat, and mouse PC are very similar to those of freshly isolated PC, whereas phase II enzyme activities are affected by cryopreservation. The American Society for Pharmacology and Experimental Therapeutics