Metabolism of 2,4-dinitrotoluene and 2,6-dinitrotoluene, and their dinitrobenzyl alcohols and dinitrobenzaldehydes by Wistar and Sprague-Dawley rat liver microsomal and cytosl fractions.
作者:Masa-aki MORI、Tadashi KAWAJIRI、Michio SAYAMA、Tatsuro MIYAHARA、Hiroshi KOZUKA
DOI:10.1248/cpb.37.1904
日期:——
The metabolism of 2, 4-dinitrotoluene (2, 4-DNT), 2, 4-dinitrobenzyl alcohol (2, 4-DNB), 2, 4-dinitrobenzaldehyde(2, 4-DNBAl), 2, 6-DNT, 2, 6-DNB and 2, 6-DNBAl in the microsomal and cytosol fractions prepared from unfortified male Wistar and male Sprague-Dawley (S.D.) rat livers was investigated. Data obtained by high-performance liquid chromatography (HPLC) indicated that the products of dinitrotoluenes (2, 4-DNT and 2, 6-DNT), dinitrobenzyl alcohols (2, 4-DNB and 2, 6-DNB), and dinitrobenzaldehydes (2, 4-DNBAl and 2, 6-DNBAl) in the microsomal and cytosol preparations containing nicotinamide adenine dinucleotide phosphate (NAD(P)) and reduced NAD(P)(NAD(P)H) were dinitrobenzyl alcohols (2, 4-DNB and 2, 6-DNB), dinitrobenzaldehydes (2, 4-DNBAl and 2, 6-DNBAl), and dinitrobenzoic acids (2, 4-DNBA and 2, 6-DNBA), and dinitrobenzyl alcohols (2, 4-DNB and 2, 6-DNB), respectively. From these results, it was concluded that the dinitrobenzaldehydes (2, 4-DNBAl and 2, 6-DNBAl) were intermediates in the oxidations of dinitrobenzyl alcohols (2, 4-DNB and 2, 6-DNB) to dinitrobenzoic acids (2, 4-DNBA and 2, 6-DNBA), and that the oxidations of dinitrobenzyl alcohols (2, 4-DNB and 2, 6-DNB) to dinitrobenzaldehydes (2, 4-DNBAl and 2, 6-DNBAl) and the reductions of dinitrobenzaldehydes to dinitrobenzyl alcohols (2, 4-DNB and 2, 6-DNB) were reversible The result of the consecutive oxidations of 2, 6-DNT in male Wistar rat livers, in the presence of various inhibitors suggests that oxidation of 2, 6-DNT to 2, 6-DNB is done mainly by microsomal cytochrome P-450, oxidation of 2, 6-DNB to 2, 6-DNBAl is mediated by microsomal cytochrome P-450 and nicotinamide adenine dinucleotide (NAD)-dependent alcohol dehydrogenase, oxidation of 2, 6-DNBAl to 2, 6-DNBA may be mediated by NAD-dependent aldehyde oxidase, and reduction of 2, 6-DNBAl to 2, 6-DNB may be mediated by reduced NAD(NADH)-dependent aldehyde reductase. From the comparative investigation of these reaction activities, it was found that : (a) the activity in the 2, 6-DNT oxidation to 2, 6-DNB was higher than that in the 2, 4-DNT oxidation to 2, 4-DNB in both strains, and the activity in Wistar rat was higher than that in S.D. rat; (b) the activities for the reductions of the dinitrobenzaldehydes (2, 4-DNBAl and 2, 6-DNBAl) to dinitrobenzyl alcohols (2, 4-DNB and 2, 6-DNB) were the highest, among the reactions examined, in both strains, and the reduction activity of 2, 4-DNBAl to 2, 4-DNB in Wistar rat was particularly high; (c) the activity for 2, 6-DNB oxidation to 2, 6-DNBAl was higher than that for 2, 4-DNB oxidation to 2, 4-DNBAl in both strains, and the activity in Wistar rat was higher than that in S.D. rat; (d) the activity for 2, 6-DNBAl oxidation to 2, 6-DNBA was much less than that for 2, 4-DNBAl oxidation to 2, 4-DNBA in both strains, and in particular, the activity for oxidation of 2, 6-DNBAl to 2, 6-DNBA in Wistar rat was low. The present results indicate that the metabolism of DNT isomers differs in different strains of rat.
对未增强的雄性Wistar和雄性Sprague-Dawley (S.D.)大鼠肝脏中的微粒体和细胞质部分中的2, 4-二硝基甲苯 (2, 4-DNT)、2, 4-二硝基苄醇 (2, 4-DNB)、2, 4-二硝基苯甲醛 (2, 4-DNBAl)、2, 6-DNT、2, 6-DNB和2, 6-DNBAl的代谢进行了研究。通过高效液相色谱 (HPLC) 获得的数据表明, 在含有烟酰胺腺嘌呤二核苷酸磷酸 (NAD(P)) 和还原型NAD(P)(NAD(P)H) 的微粒体和细胞质制备物中, 二硝基甲苯 (2, 4-DNT和2, 6-DNT)、二硝基苄醇 (2, 4-DNB和2, 6-DNB) 和二硝基苯甲醛 (2, 4-DNBAl和2, 6-DNBAl) 的产物分别是二硝基苄醇 (2, 4-DNB和2, 6-DNB)、二硝基苯甲醛 (2, 4-DNBAl和2, 6-DNBAl) 和二硝基苯甲酸 (2, 4-DNBA和2, 6-DNBA), 以及二硝基苄醇 (2, 4-DNB和2, 6-DNB)。从这些结果可以得出结论, 二硝基苯甲醛 (2, 4-DNBAl和2, 6-DNBAl) 是二硝基苄醇 (2, 4-DNB和2, 6-DNB) 氧化为二硝基苯甲酸 (2, 4-DNBA和2, 6-DNBA) 的中间体, 并且二硝基苄醇 (2, 4-DNB和2, 6-DNB) 氧化为二硝基苯甲醛 (2, 4-DNBAl和2, 6-DNBAl) 和二硝基苯甲醛还原为二硝基苄醇是可逆的。在雄性Wistar大鼠肝脏中连续氧化2, 6-DNT的结果, 在存在各种抑制剂的情况下, 表明2, 6-DNT氧化为2, 6-DNB主要是由微粒体细胞色素P-450完成的, 2, 6-DNB氧化为2, 6-DNBAl是由微粒体细胞色素P-450和烟酰胺腺嘌呤二核苷酸 (NAD) 依赖性醇脱氢酶介导的, 2, 6-DNBAl氧化为2, 6-DNBA可能由NAD依赖性醛氧化酶介导, 而2, 6-DNBAl还原为2, 6-DNB可能由还原型NAD(NADH) 依赖性醛还原酶介导。从这些反应活性的比较研究中发现: (a) 2, 6-DNT氧化为2, 6-DNB的活性高于2, 4-DNT氧化为2, 4-DNB, 在两种菌株中, Wistar大鼠的活性高于S.D.大鼠; (b) 在两种菌株中, 二硝基苯甲醛 (2, 4-DNBAl和2, 6-DNBAl) 还原为二硝基苄醇 (2, 4-DNB和2, 6-DNB) 的活性是最高的, 在Wistar大鼠中2, 4-DNBAl还原为2, 4-DNB的活性尤其高; (c) 2, 6-DNB氧化为2, 6-DNBAl的活性高于2, 4-DNB氧化为2, 4-DNBAl, 在两种菌株中, Wistar大鼠的活性高于S.D.大鼠; (d) 2, 6-DNBAl氧化为2, 6-DNBA的活性远低于2, 4-DNBAl氧化为2, 4-DNBA, 特别是在Wistar大鼠中2, 6-DNBAl氧化为2, 6-DNBA的活性很低。本研究结果表明, 不同菌株大鼠中DNT异构体的代谢方式不同。