Metabolism of Nicotine in Smokers and Nonsmokers
While a number of secondary reinforcers may exert some influence on cigarette smoking behavior, the major factor responsible for tobacco habituation is believed to be nicotine. Two studies on the metabolism of the N-oxidative metabolites have revealed substantial in vivo reduction of these compounds to nicotine after their chronic and subchronic administration to rats. Nicotine-N,N’-dioxide was also shown to be back-reduced to the parent alkaloid as evidenced by high levels of nicotine and cotinine in the plasma and urine of treated rats. In another study, the rate of elimination of cotinine in smokers and passively exposed nonsmokers was measured. Ten smokers quit smoking and the elimination of cotinine in plasma and urine was measured for eight days after cessation. Four nonsmokers were exposed to a sidestream smoke-polluted environment and the rate of cotinine disappearance was assessed. Cotinine elimination in the plasma of the passively exposed nonsmokers took at least twice as long as that of chronic cigarette smokers. The rate of elimination from the urine was also significantly slower in nonsmokers when compared with smokers. A new nicotine delivery method, a nicotine aerosol rod, was examined under standard FTC machine smoking conditions. In a pilot study, the uptake of nicotine from this nicotine aerosol rod was also measured in smokers and nonsmokers. The results indicated that per puff deliveries of nicotine were too small to be assessed by radioimmunoassay and that this method of nicotine delivery did not result in smoker satisfaction. More work is necessary if alternate methods of nicotine delivery are to be accepted by the population which continues to smoke.
KeywordsUrinary Cotinine Cotinine Concentration Nicotine Delivery Mainstream Smoke Smoking Mother
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