Ton C C, Fong L Y
Carcinogenesis. 1984 Apr;5(4):533-6. doi: 10.1093/carcin/5.4.533.
The influence of ascorbate deficiency and megadosage on the metabolism of N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) was investigated in the guinea pig. After 21 days on a scorbutogenic diet, microsomal cytochrome P-450 and cytochrome b5 levels fell by 51 and 32%, respectively, while cytochrome c reductase activity remained constant. The activities of NDMA and NDEA dealkylase I were also depressed significantly. The Vmax of NDMA demethylase I and NDEA deethylase I was significantly depressed. Also, ascorbate deficiency significantly decreased the plasma clearance of both nitrosamines though the LD50 of neither were altered by ascorbate nutrition. Covalent binding of 14C from [14C]NDMA and [14C]NDEA to DNA obtained from liver slices was significantly lower in the deficient than in the control samples; megadosage appeared to have the opposite effect.
在豚鼠中研究了抗坏血酸缺乏和大剂量使用对N-亚硝基二甲胺（NDMA）和N-亚硝基二乙胺（NDEA）代谢的影响。在致坏血病饮食21天后，微粒体细胞色素P-450和细胞色素b5水平分别下降了51%和32%，而细胞色素c还原酶活性保持不变。NDMA和NDEA脱烷基酶I的活性也显著降低。NDMA脱甲基酶I和NDEA脱乙基酶I的Vmax显著降低。此外，抗坏血酸缺乏显著降低了两种亚硝胺的血浆清除率，尽管抗坏血酸营养状态并未改变两者的半数致死剂量（LD50）。与对照组相比，缺乏抗坏血酸的样本中，[14C]NDMA和[14C]NDEA中的14C与肝切片DNA的共价结合显著降低；大剂量使用抗坏血酸似乎具有相反的效果。
