代谢
间二甲苯(m-XYL)已被证明能够以器官和同种酶特异性的方式改变细胞色素P-450(CYP)的活性。这项工作的目的是确定m-XYL代谢为抑制性代谢物m-甲苯醛(m-ALD)是否是吸入m-XYL(100、300 ppm)、3-甲基苄醇(3-MBA)(50、100 ppm)或m-ALD(50、100 ppm)后抑制CYP同种酶的原因。大鼠单次6小时吸入m-XYL以剂量依赖性方式抑制了肺CYPs 2B1、2E1和4B1。吸入3-MBA以剂量依赖性方式抑制了肺CYPs 2B1和4B1。m-ALD以剂量依赖性方式抑制了肺CYPs 2B1和2E1,而4B1活性则剂量依赖性地增加。鼻腔粘膜CYP 2B1和2E1活性在m-XYL剂量依赖性暴露后受到抑制,3-MBA以剂量依赖性方式抑制了鼻腔粘膜CYPs 2E1和4B1。吸入m-ALD后,CYPs 2B1、2E1和4B1以剂量依赖性方式受到抑制。通过高效液相色谱(HPLC)分析,m-ALD在体内暴露于m-XYL、m-ALD和3-MBA后以剂量依赖性方式被检测到,鼻腔粘膜和肺中的m-ALD水平最高。m-XYL改变细胞色素P-450活性可能导致毒性增加或减少,以器官特异性的方式改变共暴露情景中外源性化合物的代谢轮廓。
... m-Xylene (m-XYL) has been shown to alter cytochrome P-450 (CYP) activity in an organ- and isozyme-specific manner. The purpose of this work was to determine if the metabolism of m-XYL to the inhibitory metabolite m-tolualdehyde (m-ALD) is the cause of inhibition of CYP isozymes following in vivo inhalation exposure to m-XYL (100, 300 ppm), 3-methylbenzyl alcohol (3-MBA) (50, 100 ppm), or m-ALD (50, 100 ppm). A single 6-hr inhalation exposure of rats to m-XYL inhibited pulmonary CYPs 2B1, 2E1, and 4B1 in a dose-dependent manner. Inhalation of 3-MBA inhibited pulmonary CYPs 2B1 and 4B1 in a dose-dependent manner. m-ALD inhibited pulmonary CYPs 2B1 and 2E1 in a dose-dependent manner, while 4B1 activity was increased dose dependently. Nasal mucosa CYP 2B1 and 2E1 activity was inhibited following exposure to m-XYL dose dependently, 3-MBA inhibited nasal mucosa CYPs 2E1 and 4B1 dose dependently. CYPs 2B1, 2E1, and 4B1 were inhibited in a dose-dependent fashion following inhalation of m-ALD. Following high-performance liquid chromatography (HPLC) analysis, m-ALD was detected after in vivo exposure to m-XYL, m-ALD, and 3-MBA in a dose-dependent manner, with highest m-ALD levels in the nasal mucosa and lung. Alteration of cytochrome P-450 activity by m-XYL could result in increased or decreased toxicity, changing the metabolic profiles of xenobiotics in coexposure scenarios in an organ-specific manner.
来源:Hazardous Substances Data Bank (HSDB)