PMID: 9630843Jun 19, 1998Paper

Involvement of CYP3A1, 2B1, and 2E1 in C-8 hydroxylation and CYP 1A2 and flavin-containing monooxygenase in N-demethylation of caffeine; identified by using inducer treated rat liver microsomes that are characterized with testosterone metabolic patterns

Chemico-biological Interactions
W G ChungY N Cha

Abstract

Caffeine (CA) is oxidized by rat liver microsomal enzymes to theobromine (TB), paraxanthine (PX), and theophylline (TP) by N-demethylation and to trimethylurate (TMU) by C-8 hydroxylation, In order to identify the specific enzymes responsible for productions of these primary CA metabolites, liver microsomes enriched with various isoforms of cytochrome P450 (CYP) and flavin-containing monooxygenase (FMO) are prepared by pretreatment of rats with several inducers. The specific increases in various CYP or FMO activities are identified with the diagnostic testosterone metabolic patterns or the thiobenzamide S-oxidation assay. They are then employed to metabolize the CA. Liver microsomes isolated from rats pretreated with phenobarbital (PB-microsomes) did not have increased FMO activity but had increased activities for hydroxylating the testosterone at 6 beta-(CYP3A1), 16 beta-(CYP2B1), and 2 beta-(CYP3A1) positions. This PB-microsomes had increased activity for TMU production from CA (result of C-8 hydroxylation). Liver microsomes isolated from rats pretreated with acetone (AC-microsomes) had a normal level of FMO activity but had enhanced rates of 6 beta-(CYP3A1) and 2 beta-(CYP3A1) hydroxylations of testosterone. The AC-microsome...Continue Reading

References

May 1, 1992·Xenobiotica; the Fate of Foreign Compounds in Biological Systems·G J HorbachC F Van Bezooijen
Jun 1, 1990·British Journal of Clinical Pharmacology·D SesardicD S Davies
May 15, 1987·Archives of Biochemistry and Biophysics·A J SonderfanA Parkinson
Jan 15, 1981·Biochemical and Biophysical Research Communications·J R Cashman, R P Hanzlik
May 18, 1994·Biochemical Pharmacology·W TassaneeyakulJ O Miners
Jan 1, 1993·Annual Review of Pharmacology and Toxicology·D M Ziegler

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Citations

Dec 9, 2003·Research in Veterinary Science·B SzotákováL Skálová
Jun 9, 2001·Food and Chemical Toxicology : an International Journal Published for the British Industrial Biological Research Association·K WaltonA G Renwick
May 10, 2003·Food and Chemical Toxicology : an International Journal Published for the British Industrial Biological Research Association·Seung Duk Ryu, Woon Gye Chung
Nov 8, 2001·Toxicology in Vitro : an International Journal Published in Association with BIBRA·T M Walker, A J Woodrooffe
Jul 1, 2002·Environmental Toxicology and Pharmacology·Mariëlla E M Kuilman-WahlsJohanna Fink-Gremmels
Jun 6, 2006·British Journal of Pharmacology·Anna M LeeRachel F Tyndale
Jan 25, 2012·Journal of Applied Toxicology : JAT·Patrick B KyleRobert E Kramer
Apr 20, 2001·Chemico-biological Interactions·G J SchaafJ Fink-Gremmels
Dec 19, 2002·Xenobiotica; the Fate of Foreign Compounds in Biological Systems·S L EeckhoudtR K Verbeeck
Jul 1, 1999·Alternatives to Laboratory Animals : ATLA·S CoeckeC Westmoreland
Mar 21, 2000·Chemico-biological Interactions·J G HengstlerF Oesch

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