Gender differences in activities of mouse esterase and sensitivities to DFP and sarin toxicity

1. Gender differences in the toxicity of diisopropylfluorophosphate (DFP; 4.0 mg/kg) and isopropyl methylphosphonofluoridate (sarin; 0.3 mg/kg) were studied in mice. 2. The animals were killed 3 hr after intraperitoneal (IP) injection of the organophosphates (OPs). 3. Although the activity of plasma butyrylcholinesterase (BChE) was two-fold higher and carboxylesterase (CaE) 1.3-fold higher in females than in males, the elevated BChE and CaE activities did not prevent inhibition of the enzyme by OPs in brain. 4. The differences in plasma BChE and CaE activities do not seem to be critical for the detoxification of OPs used in this study.