Influence of experimental hepatic impairment on the toxicokinetics and the anticholinesterase activity of carbaryl in the rat.

The blood kinetics of carbaryl were followed over 24 h after oral administration of 14C-carbaryl at 20 mg kg (0.17 mu Ci mg-1) in control animals and in animals with an altered liver function (70% hepatectomy or tranylcypromine treatment). The variations in the primary toxicity of carbaryl were assessed by measuring the inhibition of the plasma and erythrocyte cholinesterases and by evaluation of the lethal doses. The 14C radioactivity in the blood and, in parallel, cholinesterase inhibition were maintained at a higher level in animals with an altered hepatic function. A study of acute toxicity also showed a decrease of the LD50 (91 mg kg-1 with tranylcypromine, 342 mg kg-1 in the hepatectomized group) in the treated animals, with respect to the controls (585 mg kg-1). In all cases, tranylcypromine had a greater effect on blood kinetics, cholinesterase inhibition and LD50 than did 70% hepatectomy.