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Characterization of mouse small intestinal cytochrome P450 expression
Qing-Yu Zhang1, Debbie Dunbar, Laurence S Kaminsky
1New York State Department of Health, Wadsworth Center, P.O. Box 509, Albany, NY 12201-0509, USA.
Drug Metabolism and Disposition: the Biological Fate of Chemicals
|October 23, 2003
Summary
This study characterizes cytochrome P450 (P450) enzyme expression and induction in mouse small intestines, crucial for drug metabolism research. Key P450s are identified, and their responses to inducers like dexamethasone and phenobarbital are detailed.
Area of Science:
- Pharmacology
- Biochemistry
- Genetics
Background:
- Biotransformation enzyme expression in the mouse small intestine is not well understood.
- This knowledge gap hinders the use of mouse models for studying drug metabolism.
Purpose of the Study:
- To systematically analyze the composition and inducibility of cytochrome P450 (P450) protein and mRNA in mouse enterocytes.
- To compare P450 expression between commonly used mouse strains (C57BL/6 and 129/sv).
Main Methods:
- RNA-PCR and real-time quantitative RNA-PCR were used to identify and quantify P450 mRNA.
- Immunoblot analysis was performed to detect P450 protein levels.
- Enzyme induction was studied using dexamethasone (DEX), phenobarbital (PB), and beta-naphthoflavone (BNF).
Main Results:
- Multiple CYP isoforms (CYP1A1, 1B1, 2B, 2C, 2E1, 3A) were detected in mouse enterocytes.
- Dexamethasone induced all five CYP3A forms, phenobarbital induced specific CYP2B and CYP2C forms, and beta-naphthoflavone induced CYP1A1.
- CYP2B, 2C, and 3A proteins, along with CYP1A1 inducibility, showed proximal high expression decreasing distally.
- No significant strain differences were observed in CYP2B, 2C, and 3A expression or induction between C57BL/6 and 129/sv mice, but CYP1A1 induction by BNF differed.
Conclusions:
- This study provides a comprehensive characterization of P450 expression and induction in mouse small intestinal enterocytes.
- The findings are valuable for selecting appropriate mouse models in drug metabolism research.
- Differences in CYP1A1 inducibility between mouse strains warrant consideration in experimental design.
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