RT Journal Article
SR Electronic
T1 CYP2A5/CYP2A6 Expression in Mouse and Human Hepatocytes Treated with Various in Vivo Inducers
JF Drug Metabolism and Disposition
JO Drug Metab Dispos
FD American Society for Pharmacology and Experimental Therapeutics
SP 1321
OP 1326
VO 28
IS 11
A1 Marı́a Teresa Donato
A1 Pirkko Viitala
A1 Cristina Rodriguez-Antona
A1 Aija Lindfors
A1 Jose V. Castell
A1 Hannu Raunio
A1 Maria Jose Gómez-Lechón
A1 Olavi Pelkonen
YR 2000
UL http://dmd.aspetjournals.org/content/28/11/1321.abstract
AB Induction of coumarin 7-hydroxylation, catalyzed by CYP2A5 in mice and CYP2A6 in humans by various known in vivo murine inducers and modifiers, was compared in human and mouse hepatocytes in culture. Phenobarbital and rifampicin were efficient inducers (up to 10-fold induction) after 48-h treatment in murine cultured hepatocytes, whereas the enzyme activity in human hepatocytes was much more refractory to induction. However, a prolongation of incubation time to 72 h in human hepatocytes led to a modest restoration of inducibility by phenobarbital. Of the three porphyrinogenic inducers studied, griseofulvin induced the murine enzyme efficiently, but not the human enzyme, whereas aminotriazole and thioacetamide had no effect on either species. Pyrazole produced substantial induction in both human and murine hepatocytes, whereas cobalt chloride, which is also an in vivo inducer of the mouse enzyme, had no effect. Clofibric acid, an in vivo depressor of coumarin 7-hydroxylase, also depressed hepatocyte activities. In both murine and human hepatocytes, changes in CYP2A5/6 mRNA levels correlated roughly with enzyme changes, except in the case of cobalt chloride, which increased mRNA levels despite a lack of effect on enzyme activity. In general, human and mouse hepatocytes gave a similar response to CYP2A inducers. However, some differences were found, which means that, although CYP2A isozymes are probably regulated in a similar manner in both species, it is necessary to be cautious before extrapolating to human the results found in mouse models. The American Society for Pharmacology and Experimental Therapeutics