Hirano S, Tsukamoto N, Suzuki K T
National Institute for Environmental Studies, Ibaraki, Japan.
Toxicol Lett. 1990 Jan;50(1):97-105. doi: 10.1016/0378-4274(90)90256-l.
Acute biochemical changes in the rat lung and liver following intratracheal instillation of cadmium oxide (CdO) were observed at a dose of 5 micrograms Cd/rat to investigate the defense mechanism to Cd intoxication via airway. In the lung metallothionein (MT) was induced, reaching a maximum at 2 days. A slight increase in reduced glutathione (GSH) concentration was observed at 4 days. The activity of glucose-6-phosphate dehydrogenase (G6PDH) was increased and superoxide dismutase (SOD) activity was slightly decreased, but glutathione peroxidase (GPx) and glutathione reductase (GR) activities were not changed. These observations suggested that MT played a key role in detoxification of instilled CdO, but that the antioxidant enzymes had a minimal role. In the liver MT and GSH concentrations were diminished 7 h after instillation and returned to their control levels. Hepatic GPx activity was increased 1 day after instillation and the significantly elevated level lasted up to 7 days, while hepatic GR activity was decreased. These hepatic biochemical changes are suggested to be due to the secondary effects of the lung injury.
为了研究通过气道对镉中毒的防御机制，以5微克镉/大鼠的剂量经气管内滴注氧化镉（CdO），观察大鼠肺和肝脏的急性生化变化。在肺中，金属硫蛋白（MT）被诱导，在2天时达到最大值。在4天时观察到还原型谷胱甘肽（GSH）浓度略有增加。葡萄糖-6-磷酸脱氢酶（G6PDH）的活性增加，超氧化物歧化酶（SOD）活性略有下降，但谷胱甘肽过氧化物酶（GPx）和谷胱甘肽还原酶（GR）的活性没有变化。这些观察结果表明，MT在滴注的CdO解毒中起关键作用，但抗氧化酶的作用最小。在肝脏中，MT和GSH浓度在滴注后7小时降低，并恢复到对照水平。肝脏GPx活性在滴注后1天增加，显著升高的水平持续到7天，而肝脏GR活性降低。这些肝脏生化变化被认为是肺损伤的继发效应所致。
