title: Quantitative analysis of 3'-hydroxynorcotinine in human urine.
abstract: BACKGROUND
  Based on previous metabolism studies carried out in patas monkeys, we hypothesized that urinary 3'-hydroxynorcotinine could be a specific biomarker for uptake and metabolism of the carcinogen N'-nitrosonornicotine in people who use tobacco products.
  
  
  METHODS
  We developed a method for quantitation of 3'-hydroxynorcotinine in human urine. [Pyrrolidinone-(13)C4]3'-hydroxynorcotinine was added to urine as an internal standard, the samples were treated with β-glucuronidase, partially purified by solid supported liquid extraction and quantified by liquid chromatography-electrospray ionization-tandem mass spectrometry.
  
  
  RESULTS
  The method was accurate (average accuracy = 102%) and precise (coefficient of variation = 5.6%) in the range of measurement. 3'-Hydroxynorcotinine was detected in 48 urine samples from smokers (mean 393±287 pmol/ml urine) and 12 samples from individuals who had stopped smoking and were using the nicotine patch (mean 658±491 pmol/ml urine), but not in any of 10 samples from nonsmokers.
  
  
  CONCLUSIONS
  Since the amounts of 3'-hydroxynorcotinine found in smokers' urine were approximately 50 times greater than the anticipated daily dose of N'-nitrosonornicotine, we concluded that it is a metabolite of nicotine or one of its metabolites, comprising perhaps 1% of nicotine intake in smokers. Therefore, it would not be suitable as a specific biomarker for uptake and metabolism of N'-nitrosonornicotine. Since 3'-hydroxynorcotinine has never been previously reported as a constituent of human urine, further studies are required to determine its source and mode of formation.
authors.affiliation: Masonic Cancer Center, University of Minnesota, Minneapolis, MN.
authors.forename: Pramod
authors.initials: P
authors.lastname: Upadhyaya
authors.affiliation: Masonic Cancer Center, University of Minnesota, Minneapolis, MN hecht002@umn.edu.
authors.forename: Stephen S
authors.initials: SS
authors.lastname: Hecht
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000652:urine*; D002273:Carcinogens / Q000032:analysis; D002853:Chromatography, Liquid; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009538:Nicotine / Q000008:administration & dosage*; D009602:Nitrosamines / Q000652:urine*; D015203:Reproducibility of Results; D012907:Smoking / Q000652:urine; D016540:Smoking Cessation; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D015415:Biomarkers; D002273:Carcinogens; D009602:Nitrosamines; D009538:Nicotine; C008655:N'-nitrosonornicotine