RESUMO
Effect of acute exposure (24 hr) to different oral doses of dimethoate on hepatic microsomal cytochrome P-450 (Cyt. P-450) content and cytosolic glutathione S-transferase (GST) activity were determined in pigeon and rat to ascertain difference in the metabolic response as a measure of species selective toxicity. Dimethoate at five different doses caused a statistically significant decrease in Cyt. P-450 content both in pigeon and rat. However, reduction in GST activity was significant at three doses in pigeon and at high dose in rat. Thus, a different quantum of hepatic Cyt. P-450 decrease and a differed response of GST activity against dimethoate exposure in pigeon and rat may be one of the possible causes for relatively higher toxicity of dimethoate in birds.