Assessment of diisopropylfluorophosphate (DFP) toxicity and tolerance in rats.

Single s.c. injection of 1, 2, 3 or 4 mg/kg of DFP in saline was given to male rats. Control rats received saline. Beginning 24 hr after injections, body weights and food and water consumption were measured at 24 hr intervals. The 1 and 2 mg/kg DFP-treated group maintained these parameters at levels equal to those of the controls. The other DFP-treatment groups showed significant depressions in body weights and in food and water consumption, but these groups recovered 48 and 72 hrs after DFP administration of 3 mg/kg or 4 mg/kg, respectively. Daily injections of 2, 3 or 4 mg/kg of DFP, s.c., caused significant depressions of all three parameters, with only 75% of the 2 mg/kg group showing recovery over the 14 day treatment period. Of the 2 mg/kg group, 25% died following the 6th injection, 100% of the 3 mg/kg group were dead following the 4th injection and 100% of the 4 mg/kg group were dead following the 3rd injection. Prior to deaths in all DFP-treatment groups, the decreases in body weights and in food and water consumption were progressive and dose-dependent. The data show dose-dependency of general toxicity during acute and subacute exposure to DFP and of tolerance during subacute exposure.