Fluoxetine decreases glutathione reductase in erythrocytes of chronically isolated wistar rats

Alterations in the antioxidative defense parameters upon chronic stress are considered critical for pathophysiology of stress related psychiatric disorders, and their status in blood serves as biomarker for effects of pharmacological treatments. The present study was designed to investigate the modulation of erythrocyte antioxidant enzymes (AOEs): CuZn superoxide dismutase (CuZnSOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GLR) activities and their protein expression in Wistar male rats subjected to chronic psychosocial isolation and/or to pharmacological treatment with fluoxetine. Chronically isolated animals exhibited decreased levels of serum corticosterone, as opposed to other chronic stress paradigms. In addition to that, SOD, CAT and GPx status was not altered either by chronic psychosocial isolation or by fluoxetine treatment. In contrast, GLR activity and its protein level were both markedly reduced by fluoxetine. Since, GLR is crucial for overall oxido-reductive balance through maintaining optimal ratio of reduced/oxidized glutathione level (GSH/GSSG) in erythrocytes, these results could indicate that in spite of numerous beneficial effects of fluoxetine, it may compromise both haemoglobin function and oxygen transport.