CYP2A6 Genotype but not Age Determines Cotinine Half-life in Infants and Children
نویسندگان
چکیده
The formation of cotinine, the main proximate metabolite and a biomarker of nicotine exposure, is mediated primarily by cytochrome P450 (CYP)2A6. Our aim was to determine whether higher cotinine levels in young children exposed to secondhand smoke (SHS) are a result of age-related differences in pharmacokinetics. Forty-nine participants, aged 2-84 months, received oral deuterium-labeled cotinine, with daily urine samples for up to 10 days for cotinine half-life measurement. DNA from saliva was used for CYP2A6 genotyping. The estimate of half-life using a mixed-effect model was 17.9 h (95% confidence interval: 16.5, 19.3), similar to that reported in adults. There was no statistically significant effect of sex, race, age, or weight. Children with normal-activity CYP2A6*1/*1 genotypes had a shorter half-life than those with one or two reduced-activity variant alleles. Our data suggest that higher cotinine levels in SHS-exposed young children as compared with adults are due to greater SHS exposure rather than to different cotinine pharmacokinetics.
منابع مشابه
CYP2A6 genotype, phenotype, and the use of nicotine metabolites as biomarkers during ad libitum smoking.
CYP2A6 inactivates nicotine to cotinine and cotinine to 3-hydroxycotinine. We investigated which of plasma nicotine and metabolites were most related to CYP2A6 genotype and smoking levels. We assessed demographic and smoking histories in 152 Caucasian ad libitum smokers, measured breath carbon monoxide (CO) levels, and determined plasma nicotine, cotinine, and 3-hydroxycotinine by high-performa...
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In humans, 80% of nicotine is metabolized to the inactive metabolite cotinine by the enzyme CYP2A6, which can also activate tobacco smoke procarcinogens (e.g., 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone). Previously, we demonstrated that individuals who are nicotine-dependent and have defective CYP2A6 alleles (*2, *3) smoked fewer cigarettes; however, we recognize that the genotyping method...
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Introduction: Nicotine is the psychoactive substance responsible for establishing and maintaining smoking dependence. CYP2A6 is the primary enzyme that inactivates nicotine to cotinine .Genetic variation in CYP2A6 accounts for some of the inter-individual variability in nicotine metabolism and has been indicated to influence smoking behavior and dependence. Therefore, the aim of this study was ...
متن کاملCYP2A6 gene polymorphisms impact to nicotine metabolism
Nicotine is a major addictive compound in tobacco cigarette smoke. After being absorbed by the lung nicotine is rapidly metabolized and mainly inactivated to cotinine by hepatic cytochrome P450 2A6 (CYP2A6) enzyme. Genetic polymorphisms in CYP2A6 may play a role in smoking behavior and nicotine dependence. CYP2A6*1A is the wild type of the CYP2A6 gene which is associated with normal or extensiv...
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عنوان ژورنال:
دوره 94 شماره
صفحات -
تاریخ انتشار 2013