Upadhyaya Pramod, Hecht Stephen S
Masonic Cancer Center, University of Minnesota, Minneapolis, MN.
Masonic Cancer Center, University of Minnesota, Minneapolis, MN
Nicotine Tob Res. 2015 May;17(5):524-9. doi: 10.1093/ntr/ntu206. Epub 2014 Oct 16.
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.
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.
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.
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.
基于之前在东非狒狒身上进行的代谢研究，我们推测尿中3'-羟基去甲可替宁可能是烟草制品使用者体内致癌物N'-亚硝基去甲烟碱摄取和代谢的特异性生物标志物。
我们开发了一种定量人尿中3'-羟基去甲可替宁的方法。将[吡咯烷酮-(13)C4]3'-羟基去甲可替宁作为内标添加到尿液中，样品用β-葡萄糖醛酸酶处理，通过固相支持液液萃取进行部分纯化，并通过液相色谱-电喷雾电离-串联质谱法进行定量。
该方法在测量范围内准确（平均准确度 = 102%）且精密（变异系数 = 5.6%）。在48份吸烟者的尿液样本（平均393±287 pmol/ml尿液）和12份已戒烟并使用尼古丁贴片者的样本（平均658±491 pmol/ml尿液）中检测到了3'-羟基去甲可替宁，但在10份非吸烟者的样本中均未检测到。
由于吸烟者尿液中发现的3'-羟基去甲可替宁含量比预期的N'-亚硝基去甲烟碱每日剂量大约高50倍，我们得出结论，它是尼古丁或其代谢物之一的代谢产物，可能占吸烟者尼古丁摄入量的1%。因此，它不适宜作为N'-亚硝基去甲烟碱摄取和代谢的特异性生物标志物。由于此前从未报道过3'-羟基去甲可替宁是人类尿液的成分，需要进一步研究以确定其来源和形成方式。
