Evaluation of male-mediated reproductive toxic effects of methamidophos in the mouse.

The reproductive toxicity of the insecticide methamidophos was studied in male mice. Adult male mice were treated by gavage with methamidophos at doses of 0, 1, 2 and 3 mg kg(-1) day(-1) for 4 weeks before mating with untreated females. Brain and skeletal muscle acetylcholinesterase activity was inhibited in the middle- and high-treated groups. Methamidophos treatment was associated with a decreased number of live foetuses and an increased number of dead and resorption foetuses at 2 and 3 mg kg(-1) day(-1) treated groups. The per cent morphologically normal spermatozoa were affected in the 2 and 3 mg kg(-1) day(-1) dose groups; however, sperm motility and count were decreased in the same treated groups compared to the control. Histological examination of brain, muscles, testes and epididymis revealed histological abnormalities in a dose-dependent manner. The current study demonstrated adverse effects of male methamidophos exposure on pregnancy outcome with effects on sperm parameters at 2 and 3 mg kg(-1) day(-1) .