90-Day oral toxicity of ziram: a thyrostatic and hepatotoxic study

Ziram, a dithiocarbamate fungicide, is extensively used in crop protection. Daily oral doses of ziram (5 and 25 mg kg −1 day −1) for 30, 60 and 90 days produced significant mortality in male rats. The fungicide also caused a significant increase in the thyroid:body weight ratio, histological changes, and a reduced activity of thyroid 1 25I uptake and protein bound 1 25I. However, the animals did not show any change in the clinical enzyme profile of the liver, serum and brain. It is believed that ETU, the degradation product of ziram and a known antithyroid compound, is the causative agent for the high mortality, as well as for the pronounced thyrostatic and hepatotoxic effects found in the experimental animals.