2, 4-Dinitrotoluene (2, 4-DNT), which is an industrial chemical of importance in the production of urethane foams and elastomers, is a hepatocarcinogen in rats. 2, 4-Diaminotoluene (2, 4-DAT), one of the urinary and hepatic metabolites of 2, 4-DNT, is also carcinogenic in rats. We have studied the pathways of metabolism of 2, 4-DNT in the cecal microflora of rats. 2, 4-DNT was not metabolized by this preparation in the presence of oxygen. Under anaerobic conditions, an ordered sequence of reductive metabolism was observed. 2, 4-DNT was reduced to 2-amino-4-nitrotoluene (2A4NT) and 4-amino-2-nitrotoluene (4A2NT) via 2-hydroxylamino-4-nitrotoluene (2HA4NT) and 4-hydroxylamino-2-nitrotoluene (4HA2NT), which were identified by mass spectral (MS) comparison with authentic materials. The two aminonitrotoluenes were then reduced to 2, 4-DAT. No intermediates in this sequence could be isolated. These findings indicate that rat intestinal microflora catalyze the reductive metabolism of 2, 4-DNT and suggest that the reduction of 2, 4-DNT to 2, 4-DAT may play a role in the carcinogenicity of 2, 4-DNT.
2,4-
二硝基甲苯(2,4-DNT)是生产聚
氨酯泡沫塑料和弹性体的一种重要工业
化学品,对大鼠来说是一种肝致癌物。2,4-二
氨基
甲苯(2,4-
DAT)是 2,4-DNT 的尿液和肝脏代谢物之一,也会使大鼠致癌。我们研究了 2,4-DNT 在大鼠盲肠微
生物区系中的代谢途径。在有氧条件下,这种制剂不会代谢 2,4-DNT。在厌氧条件下,观察到了有序的还原代谢顺序。2, 4-DNT 通过 2-hydroxylamino-4-nitrotrotoluene (2HA4NT) 和 4-hydroxylamino-2-nitrotoluene (4HA2NT) 还原成 2-amino-4-nitrotoluene (2A4NT)和 4-amino-2-nitrotoluene (4A2NT)。然后,这两种
氨基
硝基甲苯被还原成 2,4-
DAT。这一序列中没有分离出中间产物。这些发现表明,大鼠肠道微
生物群催化了 2,4-DNT 的还原代谢,并表明 2,4-DNT 还原成 2,4-
DAT 可能在 2,4-DNT 的致癌性中发挥了作用。