Abstract
Propofol (2,6-diisopropylphenol) is a widely-used anesthetic agent attributable to its rapid biotransformation. Liver microsomal cytochrome P450 (P450) isoforms involved in the biotransformation of propofol in rats and the effects of propofol in vivo on P450 levels in rats were investigated. Of six cDNA-expressed rat P450 isoforms tested, CYP2B1 and CYP2C11 had high catalytic activities from 5 μM and 20 μM propofol concentrations, respectively. Rates of propofol metabolism, at a substrate concentration of 20 μM based on the reported human blood concentration, were decreased by intraperitoneal treatment of propofol with male rats, in contrast to a strong induction by phenobarbital. Single intravenously administered propofol (10 mg/kg) caused the decrease of total P450 and CYP2C contents and activities of testosterone 16α-hydroxylation and propofol metabolism in liver microsomes from male rats. The suppressive effects were caused by administered propofol (10 mg/kg) twice every 4 h on CYP2B activities such as testosterone 16β-hydroxylation or pentoxyresorufin O-depentylation, in addition to the strong suppression of CYP2C function by the single propofol treatment. These results suggest that CYP2C11, presumably deactivated by propofol, has an important role in propofol metabolism in rat liver microsomes. Repeated administration of propofol could markedly decrease the biotransformation of propofol via P450 deactivation.
Footnotes
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This work was supported in part by the Ministry of Education, Science, Sports and Culture of Japan, The Research Foundation for Pharmaceutical Sciences, and Japan Research Foundation for Clinical Pharmacology.
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Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
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doi:10.1124/dmd.106.011627.
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ABBREVIATIONS: P450, cytochrome P450; ANOVA, analysis of variance.
- Received June 25, 2006.
- Accepted August 4, 2006.
- The American Society for Pharmacology and Experimental Therapeutics
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