METABOLISM AND TOXICITY OF ACID PHOSPHATE -ESTERS, METABOLITES OF ORGANOPHOSPHOROUS INSECTICIDES, IN RAT

Metabolism and toxicity of acid phosphate esters were studied in the r at. Diethyl phosphate (DEP), diethyl thiophosphate (DETP) and diisopro pyl phosphate (DIPP) were administered to rats as a dose of 1 g/kg. DE P-applied rats excreted inorganic phosphate and organic phosphate in t he 24 h urine at amounts of 53% and 13%, of the dose respectively. DET P-treated rates excreted inorganic phosphate and organic phosphate in their urine at amounts of 18% and 10%, of the dose respectively. DIPP- treated rates excreted inorganic phosphate and organic phosphate in th eir urine at amounts of 8% and 9%, of the dose respectively. The DETP- treated rats showed symptoms such as salivation, lacrimation and tremo rs. DETP intensely inhibited cholinesterase in rat brain homogenate, a nd DEP weakly inhibited the cholinesterase activity. On the other hand , DIPP did not inhibit the cholinesterase activity. The inhibition of cholinesterase induced by DETP was higher than that of diazinon.