Enzyme activities of brown trout liver and kidney peroxisomes after paraquat exposure

• Autor(a) principal: Resende, Albina Dolores
• Data de Publicação: 2025
• Outros Autores: Lobo da Cunha, Alexandre, Rocha, Eduardo
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Texto Completo: https://doi.org/10.48797/sl.2025.278
• topic: Enzyme activities; Kidney peroxisomes; Liver peroxisomes; Pesticide; Teleost

Paraquat, a potent herbicide, can be highly toxic to fish, causing morphological and biochemical alterations in several organs, including induction of oxidative stress that may result in cellular damage. Since peroxisomes are vital regulators of reactive oxygen species, it was hypothesized that a subacute exposure of brown trout – a sensitive bioindicator – to a waterborne environmentally relevant concentration (0.3 mg L-1) of paraquat may impact some liver and kidney peroxisomal enzyme activities. Spectrophotometric measurements of urate oxidase, catalase, and d-amino acid oxidase activities were assayed in liver and renal homogenates from immature trout, control and exposed, at 0, 7, and 15 days. In the liver, none of those enzymes showed significant differences between the control and exposed fish at 7 and 15 days. In the kidney, urate oxidase activity was not detectable, and no significant statistical difference was found for the other enzymatic activities between groups. However, an increase in catalase and a simultaneous decrease in d-amino acid oxidase activities were detected during the experiment. At the concentration tested, paraquat did not affect the targeted hepatic and renal peroxisomal enzymes. Additionally, the study revealed changes over time, warning that captivity or experimental stress influenced the enzyme activities.