title: Biochemical biomarkers in Scinax fuscovarius tadpoles exposed to a commercial formulation of the pesticide fipronil.
abstract: One of the main pesticides used in the cultivation of sugarcane in São Paulo State, Brazil, is Regent(®)800WG, the main active compound of which is fipronil. Fipronil is a potent insecticide that eliminates pests, including insects resistant to pyrethroids, organophosphates (OP) and carbamates (CA). There is little known on the toxic effects of fipronil on non-target organisms, such as tadpoles of frogs. It is possible that this compound carries a high toxicity for these organisms, since the pesticide can be incorporated into aquatic environments during the rainy season, a time which coincides with the time of amphibian reproduction and the occurrence of tadpoles in the aquatic environment in this region. Thus, the pesticide could be contributing to the decline of amphibians in the northwest region of São Paulo state due to its wide use. This study aimed to test the influence of Regent(®)800WG on some biochemical systems of tadpoles (such as antioxidant defense systems) at different stages of development. The results of analysis from in vivo exposures demonstrated that only a few parameters in the groups exposed to fipronil responded to exposure to Regent(®)800WG, results which indicate that the pesticide instigates biochemical responses in tadpoles. Although catalase and glucose-6-phosphate dehydrogenase (G6PDH) were unchanged during the experiments, glutathione-S-transferase (GST) was inhibited in tadpoles, and the activity of glutathione reductase (GR) varied according to the exposure period and pesticide concentration. This data demonstrated the influence of the fipronil formulation on the metabolism of tadpoles, and showed that it can increase their susceptibility to environmental contaminants.
authors.affiliation: Department of Chemistry and Environmental Sciences, São Paulo State University - São José do Rio Preto (Universidade Estadual Paulista "Júlio de Mesquita Filho"), Rua Cristóvão Colombo, 2265, 15054-000 São José do Rio Preto, SP, Brazil.
authors.forename: Tatiana Cristina
authors.initials: TC
authors.lastname: Stefani Margarido
authors.forename: Andréia Arantes
authors.initials: AA
authors.lastname: Felício
authors.forename: Denise
authors.initials: D
authors.lastname: de Cerqueira Rossa-Feres
authors.forename: Eduardo Alves
authors.initials: EA
authors.lastname: de Almeida
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis*; D004781:Environmental Exposure; D004789:Enzyme Activation / Q000187:drug effects; D005980:Glutathione Reductase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D007814:Larva / Q000187:drug effects*; D010575:Pesticides / Q000633:toxicity*; D011720:Pyrazoles / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D015415:Biomarkers; D010575:Pesticides; D011720:Pyrazoles; D014874:Water Pollutants, Chemical; D005980:Glutathione Reductase; D005982:Glutathione Transferase; C082360:fipronil
keywords: Biochemical biomarkers; Fipronil; Pesticide; Scinax fuscovarius; Tadpoles