Actue toxicity of insecticidal Methomyl in rats

Hematological, biochemical and histopathological examinations were conducted on rats administered orally 5, 10 and 15 mg/kg of Methomyl. Furthermore, mechanism of the toxic action of the drug was investigated. 1. Serum cholinesterase activity was inhibited and the clinical signs that could be associated with anticolinesterase activity appeared on animals after administration of each dose of the drug. 2. No hematological changes were observed. 3. Biochemical studies revealed the disorders in functions of livers and kidneys of rats receiving 5 mg/kg of Methomyl. Histopathological alterations were seen in lungs of rats administered 5 mg/kg and over of Methomyl, and also in livers and kidneys of animals which received 15mg/kg of the drug. 4. Rats administered 5 mg/kg and over of methomyl had a decrease in superoxide dismutase activity, an increase in serum lipoperoxide level and a decrease in serum α-tocopheraol level. The results abtained suggest that superoxide free radical may be concerned in the lesions of lungs, livers and kidneys of animals which received the drug. 5. Alpha-tocopheraol reduced the lesions of lungs, livers and kidneys of administered Methomyl.