Effect of malathion and endosulfan on brain acetylcholinesterase and ovarian steroidogenesis of Channa punctatus (Bloch).

The effect of sublethal concentrations of malathion (organophosphorus insecticide) and endosulfan (organochlorine insecticide) was investigated in Channa punctatus. Brain acetylcholinesterase (AchE) and ovarian delta 5,3 beta-hydroxysteroid dehydrogenase (delta 5,3 beta-HSD) and glucose-6-phosphate dehydrogenase (G-6-PD) activities were studied. Apart from the loss of stage II and III oocytes, the absence of delta 5,3 beta-HSD and G-6-PD activity indicating the inhibition of steroidogenesis was seen in the malathion- and endosulfan-treated fish ovaries. Malathion demonstrated a dose-dependent inhibition of brain AchE activity, whereas endosulfan caused no significant reduction of AchE activity.