Pharmacokinetics of a neurotoxic oral dose of leptophos in hens.

A pharmacokinetic profile of [14C] leptophos was determined in laying hens following a single oral dose of 400 mg/kg (0.58 muCi). Most of the radioactivity was excreted into the urine and feces. After 15 days, the total radioactivity recovered in the combined urinary-fecal excretion was 73.5% of the administered dose. A major part of the absorbed leptophos was concentrated in the eggs. The total 14C radioactivity in egg albumen was 7.29% of the administered dose as compared to 4.67% in egg yolk. The half-life for the disappearance of radioactivity from the birds' bodies following the administration of [14C] leptophos was 11.55 days. A correlation between the pharmacokinetics of leptophos and the susceptibility of the hen to delayed neurotoxicity is discusses.