RESUMEN
8-Methoxypsoralen (8-MOP) is a well established drug in the treatment of various skin diseases. Pretreatment of mice with 8-MOP before administration of 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) significantly reduced the incidence of NNK-induced tumor. The present study was designed to evaluate the in vivo effects of 8-MOP on the bioactivation of NNK in mice. Decrease in the α-hydroxylation of NNK in mouse blood and tissues was observed as the most pronounced effect of 8-MOP. The catalytic property of cytochrome P450 2A5 (CYP2A5) enzyme in mice was determined by the coumarin 7-hydroxylation reaction, suggesting that 8-MOP produced remarkable inhibition on CYP2A5 in female C57BL/6 mice. These results implied that 8-MOP could prevent NNK-induced mutagenesis and tumorigenesis in mice through the inhibition of NNK α-hydroxylation, which may be achieved through the effect of 8-MOP on the bioactivities of CYP2A5.
Asunto(s)
Metoxaleno/farmacología , Nitrosaminas/metabolismo , Animales , Hidrocarburo de Aril Hidroxilasas/metabolismo , Carcinogénesis/inducido químicamente , Carcinógenos , Catálisis/efectos de los fármacos , Cumarinas/metabolismo , Familia 2 del Citocromo P450 , Femenino , Hidroxilación/efectos de los fármacos , Imidazoles/metabolismo , Ratones , Ratones Endogámicos C57BL , Nitrosaminas/efectos adversosRESUMEN
A hydrophilic-interaction liquid chromatography-tandem mass spectrometry (HILIC-MS-MS) method was developed for the determination of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and its metabolites in mouse liver and lung. The limits of detection of all analytes were in the range 0.017-0.057 ng mL(-1), and recovery ranged from 88.4-119.8 % with intra and inter-day precision in the range 0.89-6.03 % and 1.01-6.97 %, respectively. This simple and accurate method was used to evaluate the effect of chronic alcohol consumption on NNK bioactivation in mouse tissue. Time-course curves for NNK and its metabolites were generated, and the areas under the curves (AUCs) were compared. It was found that target tissues of NNK carcinogenesis in C57BL/6 mice contained high levels of α-hydroxylation metabolites of NNK and its carbonyl reduction metabolite, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL). The most pronounced effect of alcohol was to enhance α-hydroxylation of NNK in mouse lung and liver, which suggests that chronic alcohol consumption may increase the risk of carcinogenicity associated with NNK in mice.
Asunto(s)
Alcoholismo/metabolismo , Cromatografía Liquida/métodos , Hígado/metabolismo , Pulmón/metabolismo , Nitrosaminas/análisis , Espectrometría de Masas en Tándem/métodos , Alcoholismo/fisiopatología , Animales , Área Bajo la Curva , Calibración , Femenino , Hidroxilación , Límite de Detección , Hígado/efectos de los fármacos , Hígado/patología , Pulmón/efectos de los fármacos , Ratones Endogámicos C57BL , Nitrosaminas/metabolismo , PiridinasRESUMEN
A hydrophilic interaction liquid chromatographic-tandem mass spectrometric (HILIC-MS-MS) method for investigation of the in vivo metabolism of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a potent carcinogen, in rabbit blood has been developed and validated. This method achieved excellent repeatability and accuracy. Recovery ranged from 76.9 to 116.3 % and precision (as RSD) between 0.53 and 6.52 %. Linearity was good for all compounds (R(2)>0.9990) and the limit of detection (LOD) ranged from 0.016 to 0.082 ng mL(-1). Pharmacokinetic analysis indicated that NNK was rapidly eliminated in vivo in rabbit blood and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) was the major metabolite. The hydroxy acid, keto acid, and NNAL-N-oxide were also important metabolites in rabbit blood. It is probable that α-methylene hydroxylation was the major pathway of α-hydroxylation of NNK and NNAL in the rabbit.