Antioxidant metabolism and development in Bufo arenarum embryos exposed to azynphos methyl

LASCANO C; FERRARI A; VENTURINO A

Mar del PLata

Congreso; 43ª Reunión Anual de la SAIB; 2007

SAIB

Amphibians are very susceptible to environmental contaminants, being the toad B. arenarum particularly threatened during itsembryonic development by the massive application of theorganophosphate azynphos methyl (AM) used for pest control inNorpatagonia valleys. Our objective is to determine if reactiveoxygen species (ROS) in connection with altered polyamine (PA)metabolism contribute to altered embryonic development.Embryos were continuously exposed until complete developmentto 0.5, 2 and 9mg/l AM. Antioxidant enzyme activities weremeasured. Catalase was early increased by 0.5mg/lAM returningto control levels thereafter.GSHreductase was also early increasedby all doses of AM, while GSH peroxidase tended to decrease atlate stages. GST was not affected by AM. Putrescine levelsincreased throughout development, rising significantly in exposedembryos, while spermidine and spermine were decreased in late embryos exposed to 9mg/l AM. These effects are accompanied with a dose dependent increase in the number of embryonic malformations. The results suggest that catalase and GSH reductase are early induced in response to mild exposure to AM, while in later embryonic stages the antioxidant enzymes are altered by the increase of oxidative stress. PA levels suggest an oxidative metabolization to putrescine, contributing to oxidative stress and altered development.