Acephate Insecticide Toxicity: Safety Conferred by Inhibition of the Bioactivating Carboxyamidase by the Metabolite Methamidophos
作者:Mahmoud Mahajna、Gary B. Quistad、John E. Casida
DOI:10.1021/tx9601420
日期:1997.1.1
doubles the LD50 of i.p.-administered acephate from 540 to 1140 mg/kg. Methamidophos pretreatment in rats also markedly alters the metabolism of dimethoate (another systemic insecticide) from principally carboxyamide hydrolysis to mainly other pathways. In contrast, methamidophos pretreatment of houseflies does not alter the acephate-induced toxicity and brain AChE inhibition. The safety of acephate in
乙酰甲酸酯是一种重要的全身性有机磷杀虫剂,其毒性可归因于代谢转化为甲酰磷(或其乙酰化代谢物)的甲酰胺磷(AChE)抑制剂的生物活化作用。乙酰甲胺磷的选择性毒性被认为是由于在昆虫而非哺乳动物中容易转化为甲胺磷所致。我们在本研究中表明,羧酰胺酶激活了小鼠的乙酰甲酸酯,进而受到水解产物甲胺磷的抑制。因此,开始了生物激活,但立即将其关闭。通过发现以5 mg / kg的甲胺磷ip腹腔注射对小鼠进行4 h预处理对乙酰甲酚作用具有以下关系,从而建立了上述关系:在腹膜内注射acephate剂量后的头2 h中,肝脏中的甲胺磷和乙酰甲酚水平降低了30-60%。抑制肝羧酰胺酶将[14CH3S]乙酰甲酸酯裂解为[14CH3S]甲酰胺二磷,阻滞率为50%,浓度约为1 mg / kg;在体内强烈抑制14CO2从[CH3(14)C(O)]乙酰甲酸盐释放;通过增加保留羧酰胺部分的O-和S-去甲基化产物,显着改变乙酰乙酸的