Martelli A, Robbiano L, Gazzaniga G M, Brambilla G
Institute of Pharmacology, University of Genoa, Italy.
Cancer Res. 1988 Aug 1;48(15):4144-52.
Ten carcinogenic N-nitroso compounds were assayed for DNA-damaging activity in primary cultures of human and rat hepatocytes. DNA fragmentation was measured by the alkaline elution technique, and unscheduled DNA synthesis by quantitative autoradiography. Positive dose-related responses in the range of subtoxic concentrations indicated were obtained in cells of both species with N-nitrosodiethylamine (10-32 mM), N-nitrosodi-n-propylamine (1.8-10 mM), N-nitrosomorpholine (1-3.2 mM), N-nitrosopiperidine (1-3.2 mM), N-nitrosopyrrolidine (3.2-18 mM), N-nitroso-N-methylurea (0.32-1.8 mM), N-nitroso-N-ethylurea (0.32-1.8 mM), and N-nitroso-N-butylurea (0.1-0.32 mM). N-nitrosodi-n-butylamine was practically inactive at the maximal soluble concentration (1 mM). The responses of human hepatocytes were qualitatively similar to those of rat hepatocytes, but statistically significant differences between the two species in the amounts of DNA damage and/or unscheduled DNA synthesis were observed with N-nitrosodimethylamine, N-nitrosomorpholine, N-nitrosopiperidine, N-nitrosopyrrolidine, and N-nitroso-N-butylurea. On the other hand, quantitative differences in the genotoxic effects induced by 5 mM N-nitrosodimethylamine in cultures derived from 20 human donors and from 20 rats were greater than average interspecies differences displayed by this nitrosamine and by other N-nitroso compounds. These results indicate that the rat hepatocyte DNA repair assay is a valid model for predicting the genotoxic potential of N-nitroso compounds in human hepatocytes.
对十种致癌性N-亚硝基化合物在原代培养的人及大鼠肝细胞中进行了DNA损伤活性检测。采用碱性洗脱技术测定DNA片段化，通过定量放射自显影术测定非预定DNA合成。在亚毒性浓度范围内观察到，N-亚硝基二乙胺（10 - 32 mM）、N-亚硝基二正丙胺（1.8 - 10 mM）、N-亚硝基吗啉（1 - 3.2 mM）、N-亚硝基哌啶（1 - 3.2 mM）、N-亚硝基吡咯烷（3.2 - 18 mM）、N-亚硝基-N-甲基脲（0.32 - 1.8 mM）、N-亚硝基-N-乙基脲（0.32 - 1.8 mM）和N-亚硝基-N-丁基脲（0.1 - 0.32 mM）在两种细胞中均产生了与剂量相关的阳性反应。N-亚硝基二正丁胺在最大可溶浓度（1 mM）时几乎无活性。人肝细胞的反应在性质上与大鼠肝细胞相似，但在用N-亚硝基二甲胺、N-亚硝基吗啉、N-亚硝基哌啶、N-亚硝基吡咯烷和N-亚硝基-N-丁基脲时，观察到两种细胞在DNA损伤量和/或非预定DNA合成量上存在统计学显著差异。另一方面，5 mM N-亚硝基二甲胺在来自20名人类供体和20只大鼠的培养物中诱导的遗传毒性效应的定量差异大于该亚硝胺和其他N-亚硝基化合物所显示的种间平均差异。这些结果表明，大鼠肝细胞DNA修复检测是预测N-亚硝基化合物对人肝细胞遗传毒性潜力的有效模型。
