ABSTRACT
Neonates are known to be more vulnerable than adults, and their susceptibility to the side effect of pesticides attracted more concern in recent years. This work was carried out to assess the sensitivity of pups to the alpha-cyano synthetic pyrethroid insecticides lambda-cyhalothrin and deltamethrin. LD[50] was used as indicator of acute toxicity. Moreover, lambda-cyhalothrin and deltamethrin at low doses [0.31 and 0.36 mg/kg bw., respectively], were given daily in corn oil throughout the lactation period. Groups of pups [5 as control + 5 from each insecticide treatment group] were with drawl and sacrificed after 4, 10 16 and 21 days, and the level of malondialdehyde [MDA] which expresses the lipid peroxidation status was estimated in the tissues of the liver and brain. At the same time, superoxide dismutase [SOD], glutathione-S-transfersase [GST] activity and reduced glutathione [GSH] level were determined in both brain and liver. Glutathione reductase [GR] and glucose-6-phosphate dehydrogenase [G6PDH] activity were estimated to evaluate the redox cycle State. Results indicated that both insecticides significantly increased lipid peroxidation and decreased the [SOD], [GR] and [G6PDH] activity and [GSH] level in liver. The effect of both pyrethroids on these parameters in brain tissue was less than that in the liver. Conclusively the results obtained suggested that both synthetic pyrethroid insecticides were able to produce oxidative stress and alter the antioxidant defense mechanisms. Furthermore, the neonates [i.e. pups in lactation period] seem to be more susceptible to pyrethroids exposure than expected