title: Fluconazole-induced hepatic cytochrome P450 gene expression and enzymatic activities in rats and mice.
abstract: This study was undertaken to examine the effects of the triazole antifungal agent fluconazole on the expression of hepatic cytochrome P450 (Cyp) genes and the activities of Cyp enzymes in male Sprague-Dawley rats and male CD-1 mice. Alkoxyresorufin O-dealkylation (AROD) methods were used as measures of Cyp enzyme activities. Western analyses identified specific Cyp isoforms. Quantitative real-time reverse-transcription polymerase chain reaction (quantitative real time-RT-PCR) assays were used to quantitate the mRNA expression of specific Cyp genes induced by this conazole. Rats and mice were administered fluconazole 2, 25, or 50 mg/kg bw/d by gavage daily for 14 days. In rats, fluconazole treatment (50 mg/kg bw/d) significantly induced pentoxyresorufin O-dealkylation (PROD), benzyloxyresorufin O-dealkylation (BROD), and ethoxyresorufin O-dealkylation (EROD) hepatic microsomal activities. Fluconazole treatment significantly increased rat hepatic mRNA expression of CYP2B1 and CYP3A23/3A1 with dose-related responses. The highest dose of fluconazole gave a 128-fold induction of CYP2B1 and a 4.6-fold induction of CYP3A23/3A1 mRNA. CYP3A2 mRNA levels were also overexpressed 5.6-7.2-fold depending on dose. Western immunoblots of rat hepatic microsomal proteins identified Cyp isoforms: CYP1A1, CYP1A2, CYP2B1/2, CYP3A23/3A1, and Cyp3A2 with increased levels of CYP2B1/2 and CYP3A23/3A1 proteins. In mice, fluconazole induced BROD, PROD, EROD, and methoxyresorufin O-dealkylation hepatic microsomal activities after treatment with 25 and 50 mg/kg bw/d. Fluconazole increased mouse hepatic mRNA expression of Cyp2b10 (1.9-fold) and Cyp3a11 (2.6-fold) in the 50 mg/kg bw/d treatment group. In summary, these results indicated that fluconazole, a triazole-containing conazole, clearly induced CYP2B and CYP3A families of isoforms in rat liver and Cyp2b and Cyp3a families of isoforms in mouse liver.
authors.affiliation: National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
authors.forename: Guobin
authors.initials: G
authors.lastname: Sun
authors.forename: Sheau-Fung
authors.initials: SF
authors.lastname: Thai
authors.forename: Guy R
authors.initials: GR
authors.lastname: Lambert
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Wolf
authors.forename: Douglas B
authors.initials: DB
authors.lastname: Tully
authors.forename: Amber K
authors.initials: AK
authors.lastname: Goetz
authors.forename: Michael H
authors.initials: MH
authors.lastname: George
authors.forename: Rachel D
authors.initials: RD
authors.lastname: Grindstaff
authors.forename: David J
authors.initials: DJ
authors.lastname: Dix
authors.forename: Stephen
authors.initials: S
authors.lastname: Nesnow
mesh_terms: D000818:Animals; D000935:Antifungal Agents / Q000009:adverse effects*; D015153:Blotting, Western; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D015725:Fluconazole / Q000009:adverse effects*; D015870:Gene Expression / Q000187:drug effects*; D008099:Liver / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009929:Organ Size / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000935:Antifungal Agents; D012333:RNA, Messenger; D015725:Fluconazole; D003577:Cytochrome P-450 Enzyme System