Zirong Xu, Shijun Bai
Key Laboratory for Molecular Animal Nutrition of Ministry of Education, Feed Science Institute, Zhejiang University Huajiachi Campus, No. 164 Qiutao North Road, Hangzhou 310029, People's Republic of China.
Ecotoxicol Environ Saf. 2007 May;67(1):89-94. doi: 10.1016/j.ecoenv.2006.04.006. Epub 2006 Jun 23.
To explore the effects of cadmium (Cd) exposure of tilapia (Oreochromis niloticus) on hepatic glutathione (GSH) metabolism, tilapias were exposed to 3.0 mg/L Cd for 1, 5, 10, 20, and 40 days. The contents of reduced GSH and oxidized GSH (GSSG) and the activities of enzymes involved in GSH metabolism and the GSSG-GSH ratio were investigated. The results showed that reduced GSH were depleted progressively whereas the GSSG-GSH ratio increased. The activities of selenium-dependent glutathione peroxidase, glutathione S-transferase and glucose-6-phosphate dehydrogenase, and GSSG levels increased initially and decreased subsequently but still higher than the controls. Glutathione reductase activity dropped on the 40th day. A transient increase in gamma-glutamylcysteine syntheses activity was detected on the 20th day. The findings demonstrated that the hepatic GSH pool showed different reaction patterns associated with exposure period. The homeostatic mechanism was activated by short-term Cd exposure while the response ability weakened for a longer exposure.
为探究罗非鱼（尼罗罗非鱼）镉（Cd）暴露对肝脏谷胱甘肽（GSH）代谢的影响，将罗非鱼暴露于3.0 mg/L Cd中1、5、10、20和40天。研究了还原型谷胱甘肽和氧化型谷胱甘肽（GSSG）的含量、参与谷胱甘肽代谢的酶活性以及GSSG-GSH比值。结果表明，还原型谷胱甘肽逐渐消耗，而GSSG-GSH比值升高。硒依赖性谷胱甘肽过氧化物酶、谷胱甘肽S-转移酶和葡萄糖-6-磷酸脱氢酶的活性以及GSSG水平最初升高，随后下降，但仍高于对照组。谷胱甘肽还原酶活性在第40天下降。在第20天检测到γ-谷氨酰半胱氨酸合成酶活性短暂增加。研究结果表明，肝脏谷胱甘肽库在不同暴露时期呈现出不同的反应模式。短期镉暴露激活了稳态机制，而长期暴露则使反应能力减弱。
