Fischer S, Spiegelhalder B, Eisenbarth J, Preussmann R
Institute for Toxicology and Chemotherapy, German Cancer Research Center, Heidelberg.
Carcinogenesis. 1990 May;11(5):723-30. doi: 10.1093/carcin/11.5.723.
The origin of tobacco-specific nitrosamines (TSNA) in mainstream smoke and the possible contribution of synthesis during the smoking procedure was investigated. Addition of the nitrosamine precursors nitrate and nicotine to the tobacco prior to smoking did not change the mainstream smoke concentrations of N'-nitrosonornicotine (NNN) and 4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK), whereas the mainstream smoke concentration of N'-nitrosoanabasine (NAB) and N'-nitrosoanatabine (NAT) increased after spiking the cigarettes with nitrate. Data for TSNA in tobacco and in mainstream smoke and for nitrate in tobacco of commercial cigarettes of the West German market, taken from previous investigations, were used to calculate the mainstream smoke/tobacco ratios for NNN and NNK. These ratios were corrected for ventilation and cigarette length. It is shown that the ratios are constant and neither depend on the nicotine level nor on the nitrate level of the tobacco except for NNK in the nitrate rich dark tobacco type cigarettes. For nonfilter cigarettes the transfer rates of NNN and NNK which had been corrected for ventilation and cigarette length amounted to 23 or 34% respectively. For filter cigarettes a transfer rate of 13% for NNN and 23% for NNK was calculated. Furthermore it is shown that the mainstream smoke/tobacco ratios for NNN and NNK are constant over the whole length of the cigarettes except for NNK in dark tobacco type cigarettes. The results of this investigation indicate that pyrosynthesis of NNN does not occur and that it is very unlikely for NNK at least for lower nitrate levels. Thus with few exceptions the TSNA burden of smokers is predominantly influenced by the amount of preformed NNN and NNK in tobacco.
研究了主流烟雾中烟草特有亚硝胺（TSNA）的来源以及吸烟过程中合成的可能贡献。在吸烟前向烟草中添加亚硝胺前体硝酸盐和尼古丁，并未改变N'-亚硝基降烟碱（NNN）和4-（甲基亚硝胺基）-1-（3-吡啶基）-1-丁酮（NNK）的主流烟雾浓度，而在用硝酸盐加标香烟后，N'-亚硝基新烟草碱（NAB）和N'-亚硝基假木贼碱（NAT）的主流烟雾浓度增加。取自先前调查的西德市场商业卷烟的烟草和主流烟雾中TSNA以及烟草中硝酸盐的数据，用于计算NNN和NNK的主流烟雾/烟草比率。这些比率针对通风和卷烟长度进行了校正。结果表明，除了高硝酸盐含量的深色烟草类型卷烟中的NNK外，这些比率是恒定的，既不取决于烟草的尼古丁水平，也不取决于硝酸盐水平。对于非过滤嘴卷烟，校正通风和卷烟长度后的NNN和NNK的转移率分别为23%或34%。对于过滤嘴卷烟，计算出NNN的转移率为13%，NNK的转移率为23%。此外还表明，除了深色烟草类型卷烟中的NNK外，NNN和NNK的主流烟雾/烟草比率在卷烟的整个长度上是恒定的。这项研究的结果表明，NNN不会发生热合成，至少对于较低的硝酸盐水平，NNK也极不可能发生热合成。因此，除了少数例外情况，吸烟者的TSNA负担主要受烟草中预先形成的NNN和NNK量的影响。
