Effect of pesticide exposure on human microsomal enzyme induction

1 The antipyrine half-life, metabolic clearance rate and the apparent volume of distribution were measured in six subjects handling malathion. These results were compared with six appropriate controls. 2 Occupational exposure of malathion in subjects reduced the antipyrine half-life from 9.18 +/- 2.16 h in controls to 4.73 +/- 1.65 h. 3 It is concluded that malathion exposure increases the rate of antipyrine elimination, possibly by inducing the hepatic microsomal enzymes.