Age dependence of O6-methylguanine-DNA methyltransferase activity and its depletion after carcinogen treatment in the teleost medaka (Oryzias latipes).
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.
Aoki
K
K
Division of Biology, National Institute of Radiological Sciences, Chiba, Japan.
Nakatsuru
Y
Y
Sakurai
J
J
Sato
A
A
Masahito
P
P
Ishikawa
T
T
D000375:Aging / Q000378:metabolism*; D000477:Alkylating Agents / Q000494:pharmacology*; D000818:Animals; D002273:Carcinogens / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D008099:Liver / Q000201:enzymology; D008746:Methylazoxymethanol Acetate / Q000031:analogs & derivatives* / Q000494:pharmacology; D008780:Methyltransferases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D019853:O(6)-Methylguanine-DNA Methyltransferase; D009990:Oryzias
D000477:Alkylating Agents; D002273:Carcinogens; D008746:Methylazoxymethanol Acetate; D008780:Methyltransferases; D019853:O(6)-Methylguanine-DNA Methyltransferase; C030667:methylazoxymethanol