DNA adduct formation from acrylamide via conversion to glycidamide in adult and neonatal mice
DNA adduct formation from acrylamide via conversion to glycidamide in adult and neonatal mice
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DOI：
10.1021/tx034108e
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发表时间：
2003-10-01
影响因子：
4.1
通讯作者：
Doerge, DR
中科院分区：
文献类型：
--
作者：
da Costa, GG;Churchwell, MI;Doerge, DR
丙烯酰胺（AA）是一种具有多种工业用途的高产量化学品；然而，最近在高温下煮熟的淀粉类食品中发现的ppm水平重新引起了全世界对AA神经毒性、生殖细胞诱变性和致癌性的关注。已经在实验动物和人类中观察到AA对其环氧化物代谢物缩水甘油酰胺（GA）的氧化代谢，并且可能与暴露于AA的许多毒性作用有关，包括体内N7-（2-氨基甲酰-2-羟乙基）鸟嘌呤（N7-GA- gua）的形成。本文描述了体外形成的两种新的ga衍生DNA加合物N3-（2-氨基甲酰-2-羟乙基）腺嘌呤（N3- ga - ade）和N1-（2-羧基-2-羟乙基）-2'-脱氧腺苷的特性。建立了一种基于LC -串联质谱和同位素稀释的N7-GA-Gua和N3-GA-Ade的灵敏定量方法，并验证了该方法可用于测定AA和GA处理的3日龄新生小鼠成体和全身DNA中DNA加合物的形成。在成年小鼠中，在肝脏、肺和肾脏中观察到DNA加合物形成，N7-GA-Gua水平约为2000加合物/10(8)个核苷酸，N3-GA-Ade水平约为20加合物/10(8)个核苷酸。与AA相比，GA组成年小鼠的加合物水平略高;然而，用GA处理的新生小鼠产生的全身DNA加合物水平比AA高5-7倍，可能反映了新生小鼠的氧化酶活性较低。成年小鼠AA处理后DNA加合物形成呈超线性剂量-反应关系，与高剂量下氧化代谢饱和一致。这些结果增加了我们对GA致突变潜力的理解，并为AA致癌的遗传毒性机制提供了进一步的证据。
Acrylamide (AA) is a high production volume chemical with many industrial uses; however, recent findings of ppm levels in starchy foods cooked at high temperature have refocused worldwide attention on the neurotoxicity, germ cell mutagenicity, and carcinogenicity of AA. Oxidative metabolism of AA to its epoxide metabolite, glycidamide (GA), has been observed in experimental animals and humans and may be associated with many of the toxic effects of AA exposure, including formation of N7-(2-carbamoyl-2-hydroxyethyl)guanine (N7-GA-Gua) in vivo. This paper describes the characterization of two new GA-derived DNA adducts formed in vitro, N3-(2-carbamoyl-2-hydroxyethyl)adenine (N3-GA-Ade) and N1-(2-carboxy-2-hydroxyethyl)-2'-deoxyadenosine. A sensitive method for quantification of N7-GA-Gua and N3-GA-Ade, based on LC with tandem mass spectrometry and isotope dilution, was developed and validated for use in measuring DNA adduct formation in selected tissues of adult and whole body DNA of 3 day old neonatal mice treated with AA and GA. In adult mice, DNA adduct formation was observed in liver, lung, and kidney with levels of N7-GA-Gua around 2000 adducts/10(8) nucleotides and N3-GA-Ade around 20 adducts/10(8) nucleotides. Adduct levels were modestly higher in adult mice dosed with GA as opposed to AA; however, treatment of neonatal mice with GA produced 5-7-fold higher whole body DNA adduct levels than with AA, presumably reflective of lower oxidative enzyme activity in newborn mice. DNA adduct formation from AA treatment in adult mice showed a supralinear dose-response relationship, consistent with saturation of oxidative metabolism at higher doses. These results increase our understanding of the mutagenic potential of GA and provide further evidence for a genotoxic mechanism in AA carcinogenesis.