[Determination of the activity of cytochrome P-450 CYP2A6 by HPLC method with caffeine as metabolizing probe].
OBJECTIVE
To establish a HPLC method for determining five major metabolites of caffeine in the urine, 5-acetylamino-6-formylamino-3-methyluracil (AFMU), 1-methylxanthine (1X), 1-methyluric acid (1U), 1,7-dimethyluric acid (17U) and 1,7-dimethylxanthine (17X) and assess the activity of cytochrome P-450 CYP2A6.


METHODS
The contents of five major metabolites of caffeine in the urine were determined by RP-HPLC method. Frequency distribution histogram was drawn by calculating the 17U/(AFMU + 1X + 1U + 17X + 17U) and then evaluated the activity of CYP2A6.


RESULTS
The frequency distribution histograms of CYP2A6 approximately indicated three distinct groups, the cut of point is 0.23 between fast metabolizer and intermediate type. And the cut of point is 0.15 between slow metabolizer and intermediate type.


CONCLUSIONS
The method is simple and rapid, suitable for the determination of metabolites of caffeine in urine. The method can be used to assay the activity of CYP2A6.
Li
Jun
J
The Center of Clinical Pharmacology, Shandong Provincial Hospital, Jinan, China. sphlijun@163.com
Peng
Xiang-qian
XQ
Zhang
Jian
J
Xu
Ji-ping
JP
D000328:Adult; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism*; D002110:Caffeine / Q000378:metabolism / Q000652:urine*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D065637:Cytochrome P-450 CYP2A6; D005260:Female; D006801:Humans; D008297:Male; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D013806:Theophylline / Q000652:urine; D014498:Uracil / Q000031:analogs & derivatives / Q000652:urine; D014527:Uric Acid / Q000031:analogs & derivatives / Q000652:urine*; D014970:Xanthines / Q000652:urine
D014970:Xanthines; D014527:Uric Acid; C030530:1-methyluric acid; D002110:Caffeine; D014498:Uracil; C053085:1-methylxanthine; C036692:5-acetylamino-6-formylamino-3-methyluracil; D013806:Theophylline; D006899:Mixed Function Oxygenases; D001189:Aryl Hydrocarbon Hydroxylases; C585710:CYP2A6 protein, human; D065637:Cytochrome P-450 CYP2A6; C021183:1,7-dimethylxanthine; C053084:1,7-dimethyluric acid