Subacute toxicity of urea herbicide, isoproturon, in male rats

Isoproturon, a substituted phenylurea herbicide, was evaluated for its cumulative toxic effect on growth, organ weight and histomorphology of different organs in adult male rats. The compound (200, 400 and 800 mg/kg/day for 6 days/week), suspended in refined groundnut oil, was administered to rats p.o. for 7 and 10 weeks. There were no definite signs and symptoms of toxicity in treated rats but the herbicide significantly decreased the weekly body weight of rats at 800 mg/kg dose. Isoproturon, in all the three doses, increased the weight of liver in a dose-dependent manner. At 800 mg/kg dose, isoproturon increased the weight of kidney and heart, and decreased the weight of epididymis. Histopathological alterations in the organs were dose-dependent. Salient microscopic changes induced by isoproturon were hepatocellular degenerative changes and focal necrosis in liver, glomerular and tubular degeneration in kidney and haemosiderosis in spleen. Testis showed degeneration and desquamation of cells of germinal layers. Tubular lumens of testis and epididymis exhibited reduced number of spermatids and spermatozoa, respectively, indicating retardation of spermatogenesis.