Diazinon concentrations and blood cholinesterase activities in rats exposed to diazinon.

The tissue distribution of diazinon and the inhibition of blood cholinesterase (ChE) activity were investigated in male rats which received a single intraperitoneal (i.p.) dose of diazinon (100 mg/kg body wt) in olive oil. Diazinon concentration in the blood reached a maximum 1-2 h after dosing. Comparing the distribution of diazinon among liver, kidney and brain in treated rats, the diazinon residue was much greater in the kidney than in other organs, being 500 times that in the liver and 11 times that in the brain at 8 h after dosing. Erythrocyte and plasma ChE activities were inhibited rapidly, but ChE inhibition was greater in the erythrocytes than in plasma.