Yamamoto T, Egashira T, Yoshida T, Kuroiwa Y
Acta Pharmacol Toxicol (Copenh). 1983 Aug;53(2):96-102. doi: 10.1111/j.1600-0773.1983.tb01875.x.
The mechanisms for the lower toxicity of fenitrothion as compared with methylparathion were investigated in male rats. The difference in the acute toxicity of the insecticides could be the more rapid decomposition of fenitrothion and fenitrooxon in rat liver than that of methylparathion and methylparaoxon. In particular, the decomposition of fenitrothion by hepatic microsomes was accelerated by increasing the insecticide concentration as the substrate. The oxygen analogues of both insecticides, fenitrooxon and methylparaoxon, were not detected in the brain after the administration of their parent compounds. From these results, it is concluded that the lower toxicity of fenitrothion as compared with methylparathion could be due to the greater rate of the decomposition of fenitrothion to its less toxic metabolites, rather than to the relative rate of penetration of the oxygen analogues into brain.
在雄性大鼠中研究了杀螟硫磷与甲基对硫磷相比毒性较低的机制。这两种杀虫剂急性毒性的差异可能在于杀螟硫磷及其氧类似物在大鼠肝脏中的分解速度比甲基对硫磷及其氧类似物更快。特别是，随着底物中杀虫剂浓度的增加，肝微粒体对杀螟硫磷的分解加速。在给予其母体化合物后，在大脑中未检测到这两种杀虫剂的氧类似物，即杀螟硫磷氧类似物和甲基对硫磷氧类似物。从这些结果可以得出结论，杀螟硫磷与甲基对硫磷相比毒性较低可能是由于杀螟硫磷分解为毒性较小的代谢物的速度更快，而不是由于氧类似物进入大脑的相对速度。
