Toxicological Research
- Volume 17
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- Pages.127-133
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- 2001
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- 1976-8257(pISSN)
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- 2234-2753(eISSN)
Phenotyping of Flavin-Containing Monooxygenase (FMO) Activity and Factors Affecting FMO Activity in Korean
- Jeon, Sun-Ho (Leejinsook Pediatrics Hospital) ;
- Park, Chang-Shin (Department of Pharmacology and Medicinal Toxicology Research Center, INHA University) ;
- Cha, Young-Nam (Department of Pharmacology and Medicinal Toxicology Research Center, INHA University) ;
- Chung, Woon-Gye (Department of Pharmacology and Medicinal Toxicology Research Center, INHA University)
- Published : 2001.07.01
Abstract
Together with cytochrome P450 (CYP), flavin-containing monooxygenase (FMO) present in liver microsomes oxidizes various endogenous and exogenous chemicals. In an effort to determine the human FMO activity, we have developed two non-invasive urine analysis methods using caffeine (CA) and ranitidine (RA) as the probe compounds. As the production of theobromine (TB) and ranitidine N-oxide (RANO) from CA and RA is catalyzed primarily by the hepatic FMO, we have assigned the urinary molar ratios of TB/CA and RA/RANO as the in vivo FMO activity. In 200 age-matched Korean volunteers, the obtained TB/CA ratio ranged from 0.4 to 15.2 (38-fold difference) and the RA/RANO ratio from 5.7 to 27.2 (4.8-fold). The FMO activity of 20's, determined by caffeine metabolism, was the highest (2.5