Abstract: Preliminary effects of α-terthienyl (α-T), a typical photo-activated insecticide, on active oxygen radicals and endogenous enzyme activity in the protective enzyme system of 4th instar Culex pipiens pallens larvae were studied by ESR analysis. The results indicated that both near ultraviolet radiation and α-T could enhance the amount of active oxygen radicals in 4th instar larvae of C. pipiens pallens, and the effect of α-T could also be increased by exposure to near ultraviolet radiation. The activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in vivo could be inhibited by α-T, maximal inhibition occurring after larvae had been exposed to near ultraviolet radiation for 3 hours, although the effects of such radiation and α-T on endogenous enzyme activity in the protective enzyme system varied between different enzymes.

Key words: α-terthienyl; Culex pipiens pallens; ESR, active oxygen radicals, enzyme activity, protective enzyme system