title: Caffeine metabolism in a healthy Spanish population: N-acetylator phenotype and oxidation pathways.
abstract: We studied the oxidative and N-acetylator caffeine metabolic profile in 107 healthy Spanish volunteers. Smokers had significantly higher N-1- and N-3-demethylations activities than nonsmokers (p = 0.03 and p = 0.02, respectively), and the three caffeine demethylations indexes were strongly correlated with each other (r > 0.7; p < 0.001). Our in vivo studies suggest that CYP1A2 is involved, at least in part, in the primary N-demethylations of caffeine. A non-normal and possibly bimodal distribution was detected in the xanthine oxidase activity (p = 0.04), with about 4% of subjects deficient of this metabolic activity. The population exhibited a trimodal distribution of acetylator phenotype determined by use of the 5-acetylamino-6-amino-3-methyluracil/1-methylxanthine ratio (normality test; p = 0.004). Seventy subjects (65.4%) were phenotyped as slow acetylators. The mutated gene frequency was 0.81, which is similar to other white populations.
authors.affiliation: Departamento de Farmacología y Psiquiatría, Facultad de Medicina, Universidad de Extremadura, Badajoz, Spain.
authors.forename: J A
authors.initials: JA
authors.lastname: Carrillo
authors.forename: J
authors.initials: J
authors.lastname: Benítez
mesh_terms: D000107:Acetylation; D000328:Adult; D002110:Caffeine / Q000378:metabolism*; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008297:Male; D010084:Oxidation-Reduction; D010641:Phenotype; D012016:Reference Values; D013030:Spain; D013997:Time Factors
chemical_list: D002110:Caffeine