LAUSR

Comparative activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR), the phase II biotransformation enzyme glutathione-S-transferase (GST), the concentrations of total glutathione (GSH), sulfhydryl groups (–SH) and the activity of the neurotoxicity biomarker acetylcholinesterase (AChE) were investigated in the livers of species belonging to the Pelophylax esculentus “complex” (parental species Pelophylax ridibundus, Pelophylax lessonae, and their hybrid Pelophylax kl. esculentus) from the wetland, Obedska bara in Serbia. The condition factor (CF) and hepato somatic index (HSI) were also calculated. All three species were caught at same locality and were exposed to the same environmental conditions. Liver SOD activity was lower in P. ridibundus than in P. kl. esculentus and P. lessonae; higher activities of CAT, GR and GST were observed in P. kl. esculentus frogs as compared to their parental species. The activity of GSH-Px was significantly lower in P. kl. esculentus. The activity of AChE was increased in P. lessonae as compared to P. kl. esculentus and P. ridibundus. Similar concentrations of GSH and —SH groups were observed in all investigated species. P. kl. esculentus had a higher CF, while the HSI was lower when compared to the parental species. Our findings suggest that the parental species (P. ridibundus and P. lessonae) possess more similar antioxidative responses to environmental conditions than the hybrid species P. kl. esculentus. The obtained results improve our understanding of the biology and physiology of these three closely related species.