Biochemical alterations induced by azinphosmethyl and carbaryl pesticides in Rhinella arenarum larvae

FERRARI ANA; LASCANO CECILIA; VENTURINO ANDRÉS

Tucumán, Argentina

Congreso; XLV Reunión Anual SAIB; 2009

SAIB

Organophosphate (OP) and carbamate pesticides act by inhibiting cholinesterase (ChE) and also they are able to induce oxidative stress and alter antioxidant enzymes. We analyze the effect of carbaryl (CB) and the OP azinphosmethyl (AM) on reduced glutathione (GSH) levels and enzymatic activities of ChE, carboxylesterases (CabE), catalase (CAT), GSH peroxidase (GPx), GSH reductase (GR), GSH transferase (GST), PKC and PKA of Rhinella arenarum larvae. The larvae (stage 25) were exposed 48 h to 3 mg/L and 6 mg/L AM or 10 mg/L and 20 mg/L CB. Enzyme activities and GSH were determined spectrophotometrically. PKC and PKA activities were measured with 32PγATP and histone. ChE and CabE were significantly inhibited by CB (78%, 64%) and AM (33%, 44%). Both pesticides increased GST (39%) and GR (72%-93%), while GSH levels and GPx were not significantly affected. CAT was significantly inhibited by pesticide exposure (20%-48%). PKC and PKA activities showed a tendency to increase in exposed larvae, differing with the response observed in early embryos in our previous works. Beside the strong inhibition of esterases as classical targets, both pesticides affect antioxidant enzymes. Larvae show an adaptive response increasing GST and GR enzymes, thus activating the GSH-dependent pathway, while CAT may be directly downregulated by the reactive oxygen species produced by pesticide metabolism