Subacute effects of a phosphorothionate pesticide on mixed function oxidases of Wistar rats

Subacute oral toxicity of a newly developed phosphorothionate insecticide (2-butenoic acid-3-(diethoxy-phosphinothioyl) methyl ester), coded as RPR-2, was studied in male rats by oral (multiple) intubation of low (0.014 mg kg(-1) day(-1)), medium (0.028 mg kg(-1) day(-1)), and high (0.042 mg kg(-1) day(-1)) dose for 90 days. The medium and high dose produced toxic symptoms along-with some mortality (20%) occurred in the high dose treated rats. The medium and high doses caused significant inhibition in cytochrome P-450 activity in liver, lung, kidney and brain tissues at 45 and 90 days. The high dose caused significant decrease in cyt.b5 activity of all the four tissues at 45 and 90 days. Whereas, medium dose brought such effect in liver and lung at 45 and 90 days. Kidney and brain cyt.b5 activity decreased significantly at 90th day due to medium dose. Low dose also caused inhibition in cyt.b5 activity in brain at 90th day. Cytochrome P-450 reductase activity was decreased significantly in liver,