Draper H H, Agarwal S, Nelson D E, Wee J J, Ghoshal A K, Farber E
Department of Nutritional Sciences, University of Guelph, Ontario, Canada.
Lipids. 1995 Oct;30(10):959-61. doi: 10.1007/BF02537489.
The effect of age and peroxidative stress on the concentration of a deoxyguanosine malondialdehyde adduct (dG-MDA) in rat tissues was investigated. Vitamin E deficiency had no effect on the dG-MDA content of liver DNA in rats fed a diet containing 10% corn oil. When 2% cod liver oil was added to this diet, the dG-MDA content of liver DNA doubled in the positive controls fed a high level of vitamin E (100 ppm dl-alpha-tocopherol), and there was a further increase when vitamin E was deleted. Neither iron nitrilotriacetate administration nor choline deficiency had any effect on the dG-MDA content of liver DNA. Carbon tetrachloride had a lowering effect. The failure of iron or carbon tetrachloride administration and of vitamin E deficiency to increase liver dG-MDA is consistent with their failure in previous experiments to affect the urinary excretion of dG-MDA. In contrast, these forms of peroxidative stress produce large increments in the urinary excretion of MDA adducts with lysine, reflecting increased formation and degradation of MDA-modified proteins. DNA appears to be protected from modification by MDA produced at extranuclear sites. The frequency of dG-MDA in different tissues of 4-month-old rats varied markedly: brain >> liver > kidneys and testes. Higher concentrations of dG-MDA were found in the liver and kidneys, but not the testes, of 25-month-old rats. The determinants of the concentration of dG-MDA in DNA merit further investigation.
研究了年龄和过氧化应激对大鼠组织中脱氧鸟苷丙二醛加合物（dG-MDA）浓度的影响。维生素E缺乏对喂食含10%玉米油饮食的大鼠肝脏DNA的dG-MDA含量没有影响。当在该饮食中添加2%的鳕鱼肝油时，喂食高水平维生素E（100 ppm dl-α-生育酚）的阳性对照中肝脏DNA的dG-MDA含量增加了一倍，而当维生素E缺失时则进一步增加。给予次氮基三乙酸铁或胆碱缺乏对肝脏DNA的dG-MDA含量均无任何影响。四氯化碳有降低作用。给予铁或四氯化碳以及维生素E缺乏未能增加肝脏dG-MDA，这与它们在先前实验中未能影响dG-MDA的尿排泄一致。相比之下，这些形式的过氧化应激会使赖氨酸的MDA加合物的尿排泄大幅增加，反映出MDA修饰蛋白的形成和降解增加。DNA似乎受到保护，免受核外部位产生的MDA的修饰。4月龄大鼠不同组织中dG-MDA的频率差异显著：脑>>肝脏>肾脏和睾丸。在25月龄大鼠的肝脏和肾脏中发现了较高浓度的dG-MDA，但在睾丸中未发现。DNA中dG-MDA浓度的决定因素值得进一步研究。
