Aoki K, Nakatsuru Y, Sakurai J, Sato A, Masahito P, Ishikawa T
Division of Biology, National Institute of Radiological Sciences, Chiba, Japan.
Mutat Res. 1993 Mar;293(3):225-31. doi: 10.1016/0921-8777(93)90073-p.
O6-Methylguanine-DNA methyltransferase (O6-MT) is considered to play an important role in the repair of DNA lesions induced by alkylating carcinogens in a wide range of animals. The activity of O6-MT was compared in liver extracts from the teleost medaka (Oryzias latipes) at various ages (3-5 years old) reared under natural conditions. O6-MT activity decreased significantly with advancing age. When medaka were exposed continuously to the alkylating agent methylazoxymethanol (MAM) acetate at levels of 0.1, 0.15 and 0.3 ppm in water, O6-MT activity was markedly reduced from days 1 to 7, with a slight increase thereafter. Furthermore, when fish were exposed to MAM acetate at levels of 1-2 ppm for 1 h and then maintained in normal tap water, O6-MT activity remained suppressed for 2 weeks, followed by a partial recovery.
O6-甲基鸟嘌呤-DNA甲基转移酶（O6-MT）被认为在多种动物中对烷基化致癌物诱导的DNA损伤修复起着重要作用。在自然条件下饲养的不同年龄（3至5岁）的硬骨鱼青鳉（Oryzias latipes）肝脏提取物中比较了O6-MT的活性。O6-MT活性随年龄增长而显著下降。当青鳉在水中以0.1、0.15和0.3 ppm的水平连续暴露于烷基化剂乙酸甲基偶氮甲醇（MAM）时，O6-MT活性在第1至7天显著降低，此后略有增加。此外，当鱼以1-2 ppm的水平暴露于乙酸MAM 1小时，然后饲养在正常自来水中时，O6-MT活性在2周内一直受到抑制，随后部分恢复。
