摘要
Fischer 344大鼠分别按自由采食(AC 组),限饲能量(RC 组),自由采食+AFB_1(黄曲霉毒素 B_1,AT 组)和限饲能量+AFB_1(RT 组)处理16周后,检测肝Ⅱ相反应酶活性。结果表明:与 AC 组或 AT 组相比,RC 组或 RT 组β-葡萄糖醛酸酶(E.C.3.2.1.31)活性提高12.37%和19.90%,谷胱甘肽 S 转移酶(E.C.2.5.1.8)(底物1-氯-2,4-二硝基苯)活性增加12.85%和11.90%。芳香基硫酸转移酶(E.C.2.8.2.1)Ⅲ,Ⅳ活性下降。提示能量限制对肝Ⅱ相反应酶活性有修饰作用。体外~3H-AFB_1-DNA 结合随 GSH 浓度升高而下降,同一浓度 GSH 条件下,RC 组~3H-AFB_1-DNA 结合明显低于 AC 组,表明 GSH 结合通路是 AFB_1的解毒通路之一,且能量限制可能通过增加谷胱甘肽 s 转移酶活性,增加 AFB_1及其代谢物与 GSH 的结合而促进解毒。
Activities of hepatic phase Ⅱ enzymes of Fischer 344 rats,which had been fed in ad libitum(Group AC),caloric restriction(Group RC),ad libitum+AFB_1(Group AT),and caloric restriction+AFB_1(Group RT)respectively for 16 weeks,were determined.The results showed that,as compared with Group AC or Group AT,the activity of β-glucuronidase in Group RC or Group RT was increased by 12.4% and 19.9% and the activity of glutathione s—transferase(Substrate,1—chloro—2,4—dinitrobenzene)was increased by 28.5% and 19.0%, but activity of arylsulfotransferases was decreased.These findings suggested that hepatic phase Ⅱ enzymes were modulated by caloric restriction.In vitro ~3H-AFB_1-DNA binding was decreased as GSH concentration in culture medium was increased and in the same GSH level ~3H-AFB_1-DNA binding in Group RC was much lower than that in Group AC.These results indicated that glutathione conjugation was one of the routes for AFB_1 detoxification. And the reason that caloric restriction promoted AFB_1 detoxification may result from caloric restriction increasing the activity of glutathione s-transferase and the conjuation be- tween GSH and AFB_1 or its metabolites.
关键词
能量限制
典曲霉毒素B1
大鼠
Caloric restriction
Aflatoxin B_1
β-glucuronidase
Glutathione s-transferase
arylsulfotransferase
DNA binding
