RT Journal Article SR Electronic T1 Metabolism of [D10]Phenanthrene to Tetraols in Smokers for Potential Lung Cancer Susceptibility Assessment: Comparison of Oral and Inhalation Routes of Administration JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 353 OP 361 DO 10.1124/jpet.111.181719 VO 338 IS 1 A1 Yan Zhong A1 Jing Wang A1 Steven G. Carmella A1 J. Bradley Hochalter A1 Diane Rauch A1 Andrew Oliver A1 Joni Jensen A1 Dorothy K. Hatsukami A1 Pramod Upadhyaya A1 Cheryl Zimmerman A1 Stephen S. Hecht YR 2011 UL http://jpet.aspetjournals.org/content/338/1/353.abstract AB Polycyclic aromatic hydrocarbons (PAHs) are believed to be among the causative agents for lung cancer in smokers. PAHs require metabolic activation for carcinogenicity. One pathway produces diol epoxides that react with DNA, causing mutations. Because diol epoxides are converted to tetraols, quantitation of tetraols can potentially be used to identify smokers who may be at higher risk for lung cancer. Our approach uses [D10]phenanthrene, a labeled version of phenanthrene, a noncarcinogenic PAH structurally analogous to carcinogenic PAH. Although smokers are exposed to PAH by inhalation, oral dosing would be more practical for phenotyping studies. Therefore, we investigated [D10]phenanthrene metabolism in smokers after administration by inhalation in cigarette smoke or orally. Sixteen smokers received 10 μg of [D10]phenanthrene in a cigarette or orally. Plasma and urine samples were analyzed for [D10]r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene ([D10]PheT), the major end product of the diol epoxide pathway, by gas chromatography-negative ion chemical ionization-tandem mass spectrometry. The ratios of [D10]PheT (oral dosing/inhalation) in 15 smokers were 1.03 ± 0.32 and 1.02 ± 0.35, based on plasma area under the concentration-time curve (0-∞) and total 48-h urinary excretion, respectively. Overall, there was no significant difference in the extent of [D10]PheT formation after the two different routes of exposure in smokers. A large interindividual variation in [D10]PheT formation was observed. These results demonstrate that the level of [D10]PheT in urine after oral dosing of [D10]phenanthrene can be used to assess individual capacity of PAH metabolism by the diol epoxide pathway.