Evidence for endogenous formation of N′-nitrosonornicotine in some long-term nicotine patch users
Open Access
- 1 January 2009
- journal article
- research article
- Published by Oxford University Press (OUP) in Nicotine & Tobacco Research
- Vol. 11 (1), 99-105
- https://doi.org/10.1093/ntr/ntn004
Abstract
Nitrosation of nicotine or its metabolites in the human body could lead to formation of the 2 carcinogenic tobacco-specific nitrosamines—N′-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). We investigated the possibility of endogenous formation of NNN in people who had stopped smoking and used the 21-mg nicotine patch for 6 months. We quantified urinary biomarkers of exposure to NNN—the sum of NNN and its pyridine-N-glucuronide, referred to as total NNN. Also measured were NNK metabolites—the sum of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its N- and O-glucuronides, referred to as total NNAL. The average decline of urinary total NNN was less drastic than that of total NNAL: 22% of baseline total NNN and 7.3% of baseline total NNAL were detected in urine 24 weeks after smoking cessation and patch use (p = .02). The average ratio of total NNN to total NNAL in the same urine samples increased from 0.14 in baseline urine to 0.38 after 24 weeks of nicotine patch use. Overall, these results demonstrate that endogenous formation of NNN may occur in nicotine patch users. However, the levels of urinary total NNN during patch use were generally extremely low. Moreover, in 10 of 20 subjects analyzed here, the rate of decline in total NNN was similar to that in total NNAL, indicating that endogenous formation of NNN is virtually nonexistent in these subjects. Supplementation with ascorbic acid could be a simple approach to block possible NNN formation in nicotine patch users.This publication has 28 references indexed in Scilit:
- Endogenous Formation of N‘-Nitrosonornicotine in F344 Rats in the Presence of Some Antioxidants and Grape Seed ExtractJournal of Agricultural and Food Chemistry, 2007
- 2′-Hydroxylation of nicotine by cytochrome P450 2A6 and human liver microsomes: Formation of a lung carcinogen precursorProceedings of the National Academy of Sciences of the United States of America, 2000
- Oral spit tobacco: addiction, prevention and treatmentNicotine & Tobacco Research, 1999
- Human exposure to endogenous N-nitroso compounds: quantitative estimates in subjects at high risk for cancer of the oral cavity, oesophagus, stomach and urinary bladder.1989
- Assessment of the risk of formation of carcinogenic N-nitroso compounds from dietary precursors in the stomachFood and Chemical Toxicology, 1987
- Effects of vitamins C and E on N‐nitroso compound formation, carcinogenesis, and cancerCancer, 1986
- Chemical studies on tobacco smoke. 52. Reaction of nicotine and sodium nitrite: formation of nitrosamines and fragmentation of the pyrrolidine ringThe Journal of Organic Chemistry, 1978
- Kinetics of Nornicotine and Anabasine Nitrosation in Relation to N ′-Nitrosonornicotine Occurrence in Tobacco and to Tobacco-Induced Cancer 2JNCI Journal of the National Cancer Institute, 1977
- Formation of N-nitroso compounds: Chemistry, kinetics, and in vivo occurrenceToxicology and Applied Pharmacology, 1975
- Ascorbate-Nitrite Reaction: Possible Means of Blocking the Formation of Carcinogenic N -Nitroso CompoundsScience, 1972