The tobacco specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a strong lung carcinogen in all species tested. To elicit its tumorigenic effects NNK requires metabolic activation which is supposed to take place via alpha-hydroxylation, whereas N-oxidation is suggested to be a detoxification pathway. The differences in the organ specific metabolism of NNK may be crucial for the organotropy in NNK-induced carcinogenesis. Therefore, metabolism of NNK was investigated in the target organ lung and in liver of Fischer 344 (F344) rats using the model of isolated perfused organs. High activity to metabolize 35 nM [5-3H]NNK was observed in both perfused organs. NNK was eliminated by liver substantially faster (clearance 6.9 +/- 1.6 ml/min, half-life 14.6 +/- 1.2 min) than by lung (clearance 2.1 +/- 0.5 ml/min, half-life 47.9 +/- 7.4 min). When the clearance is calculated for a gram of organ or for metabolically active cell forms, the risk with respect to carcinogenic mechanisms was higher in lung than in liver. The metabolism of NNK in liver yielded the two products of NNK alpha-hydroxylation, the 4-oxo-4-(3-pyridyl)-butyric acid (keto acid) and 4-hydroxy-4-(3-pyridyl)-butyric acid (hydroxy acid). In lung, the major metabolite of NNK was 4-(methylnitrosamino)-1-(3-pyridyl-N-oxide)-1-butanone (NNK-N-oxide). Substantial amounts of metabolites formed from methyl hydroxylation of NNK, which is one of the two possible pathways of alpha-hydroxylation, were detected in lung but not in liver perfusion. Formation of these metabolites (4-oxo-4-(3-pyridyl)-butanol (keto alcohol), and 4-hydroxy-4-(3-pyridyl)-butanol (diol) can give rise to pyridyloxobutylating of DNA. When isolated rat livers were perfused with 150 microM NNK, equal to a dosage which is sufficient to induce liver tumors in rat, glucuronidation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) was increased when compared to the concentration of 35 nM NNK. Nevertheless, the main part of NNK was also transformed via alpha-hydroxylation for this high concentration of NNK.

The scope of the present study was to investigate whether nicotine or cotinine will affect the metabolism of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in isolated perfused rat lungs and livers and to study the effect of starvation on pulmonary metabolism of NNK. NNK metabolism was investigated in isolated perfused liver and lung of male F344 rats perfused with 35 nM [5-3H]NNK in presence of a 1400-fold excess of the main tobacco alkaloid nicotine and its metabolite cotinine. In perfused rat livers, nicotine and cotinine inhibited NNK elimination and metabolism and led to a substantial increase of elimination half-life from 14.6 min in controls to 25.5 min after nicotine and 36.6 min after cotinine co-administration, respectively. In parallel, the pattern of NNK metabolites was changed by nicotine and cotinine. The pathway of alpha-hydroxylation representing the metabolic activation of NNK was decreased to 77% and 85% of control values, whereas N-oxidation of NNK and glucuronidation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) was increased 2.6- and 1.2-fold in presence of nicotine and cotinine, respectively. When isolated rat lungs were perfused with 35 nM NNK for 3 h neither the elimination nor the pattern of metabolites were substantially affected due to co-administration of 50 microM nicotine or cotinine. Cytochrome P450 2E1 is known to participate in the activation of NNK and can be induced by starvation. However, isolated rat lungs from male Sprague Dawley rats perfused with [1-14C]NNK at about 2 microM for 3 h, revealed only small differences in pulmonary elimination and pattern of NNK metabolites between fed and starved animals. These results suggest that nicotine and its main metabolite cotinine inhibit the metabolic activation of NNK predominantly in the liver whereas activation in lung, a main target organ of NNK induced carcinogenesis, remained almost unaffected.

Efficient Action of Sleep Pillows in Patients Suffering from Non-Organic Sleep Disorders – a Pilot Study Objective: Sleep disorders may critically affect working performance and quality of life. Sleep pillows have been traditionally used to overcome such disorders. Scientifically based clinical trials to demonstrate the efficacy are missing. Methods: 28 patients with problems falling asleep and/or staying asleep not related to psychiatric or organic diseases were investigated in an accredited sleep laboratory. The diagnosis was confirmed by polysomnography. After 2 and 4 weeks of treatment the polysomnography was repeated to document any influences by the sleep pillows. Results: The polysomnographic records showed a monotonic trend to regain an age-related distribution of the non-REM sleep stages. The REM sleep phase increased nearly twofold; however, the norm values were not reached within the 4-week period of treatment. Sleep pillows of intensity 2 were superior to those of intensity 1; a further increase to intensity 3 did not create any additional effect. Conclusion: The results demonstrate an effective treatment of non-complicated sleep disorders with sleep pillows, which has been shown with objective measurements in a sleep laboratory.

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