![]() |
|
|
Vol. 288, Issue 2, 463-471, February 1999
Wadsworth Center, Coumarin was previously found to cause tissue-selective toxicity in the
olfactory mucosa (OM) of rats and mice, with rats being the more
sensitive species. The aim of this study was to explore the role of
target tissue biotransformation in OM-selective toxicity and the
metabolic basis of the species differences in coumarin toxicity. At
least six coumarin metabolites were detected in OM microsomal
reactions, with o-hydroxyphenylacetaldehyde
(o-HPA) being the most abundant. Formation of
o-HPA was inhibited by reduced glutathione, confirming
its origin from a reactive intermediate. There were significant
differences in the rates and metabolite profiles of coumarin metabolism
in the livers of Wistar rats and C57BL/6 mice. The rates of metabolic
activation of coumarin, as indicated by the formation of
o-HPA, were comparable in OM microsomes of the two
species but about 25- and 3-fold higher in OM than in liver microsomes
of rats and mice, respectively. Thus, target tissue activation seems to
play an important role in the tissue-selective toxicity, whereas
differences in the rates of hepatic metabolism may be responsible for
the species difference in olfactory toxicity. Purified, heterologously
expressed mouse CYP2A5 and CYP2G1 produced 7-hydroxycoumarin and
o-HPA as the predominant products, respectively. Kinetic
analysis and immunoinhibition studies indicated that the OM-specific
CYP2G1 plays the major role in metabolic activation of coumarin.
Furthermore, of 13 human cytochrome P-450s (P-450s) examined, five
(CYP1A1, CYP1A2, CYP2B6, CYP2E1, and CYP3A4) were active in the
metabolic activation of coumarin, suggesting a potential risk of
coumarin toxicity in humans.
0022-3565/99/2882-0463$03.00/0
THE JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS
Copyright © 1999 by The American Society for Pharmacology and Experimental Therapeutics
This article has been cited by other articles:
![]() |
X. Zhang, J. D'Agostino, H. Wu, Q.-Y. Zhang, L. von Weymarn, S. E. Murphy, and X. Ding CYP2A13: Variable Expression and Role in Human Lung Microsomal Metabolic Activation of the Tobacco-Specific Carcinogen 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone J. Pharmacol. Exp. Ther., November 1, 2007; 323(2): 570 - 578. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. M. Jeffrey, M. J. Iatropoulos, and G. M. Williams Nasal Cytotoxic and Carcinogenic Activities of Systemically Distributed Organic Chemicals Toxicol Pathol, December 1, 2006; 34(7): 827 - 852. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Franzen, C. Carlsson, V. Hermansson, M. Lang, and E. B. Brittebo CYP2A5-MEDIATED ACTIVATION AND EARLY ULTRASTRUCTURAL CHANGES IN THE OLFACTORY MUCOSA: STUDIES ON 2,6-DICHLOROPHENYL METHYLSULFONE Drug Metab. Dispos., January 1, 2006; 34(1): 61 - 68. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. B. von Weymarn, Q.-Y. Zhang, X. Ding, and P. F. Hollenberg Effects of 8-methoxypsoralen on cytochrome P450 2A13 Carcinogenesis, March 1, 2005; 26(3): 621 - 629. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. B. Genter, K. H. Goss, and J. Groden Strain-Specific Effects of Alachlor on Murine Olfactory Mucosal Responses Toxicol Pathol, October 1, 2004; 32(6): 719 - 725. [Abstract] [PDF] |
||||
![]() |
X. Zhuo, J. Gu, M. J. Behr, P. J. Swiatek, H. Cui, Q.-Y. Zhang, Y. Xie, D. N. Collins, and X. Ding Targeted Disruption of the Olfactory Mucosa-Specific Cyp2g1 Gene: Impact on Acetaminophen Toxicity in the Lateral Nasal Gland, and Tissue-Selective Effects on Cyp2a5 Expression J. Pharmacol. Exp. Ther., February 1, 2004; 308(2): 719 - 728. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. Piras, A. Franzen, E. L. Fernandez, U. Bergstrom, F. Raffalli-Mathieu, M. Lang, and E. B. Brittebo Cell-specific Expression of CYP2A5 in the Mouse Respiratory Tract: Effects of Olfactory Toxicants J. Histochem. Cytochem., November 1, 2003; 51(11): 1545 - 1555. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. L. Born, D. Caudill, K. L. Fliter, and M. P. Purdon Identification of the Cytochromes P450 That Catalyze Coumarin 3,4-Epoxidation and 3-Hydroxylation Drug Metab. Dispos., May 1, 2002; 30(5): 483 - 487. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Oscarson Genetic Polymorphisms in the Cytochrome P450 2A6 (CYP2A6) Gene: Implications for Interindividual Differences in Nicotine Metabolism Drug Metab. Dispos., February 1, 2001; 29(2): 91 - 95. [Abstract] [Full Text] |
||||
![]() |
S. L. Born, D. Caudill, B. J. Smith, and L. D. Lehman-McKeeman In Vitro Kinetics of Coumarin 3,4-Epoxidation: Application to Species Differences in Toxicity and Carcinogenicity Toxicol. Sci., November 1, 2000; 58(1): 23 - 31. [Abstract] [Full Text] [PDF] |
||||