Overproduction of free radicals is also associated with neurodegenerative diseases like AD and PD, thus the oxidative stress effects on the whole brain, the hippocampus, and the prefrontal cortex in mice was assessed by determination of the antioxidant enzymes: glutathione peroxidases (GPx), superoxide dismutase (SOD), glutathione reductase (GR) activities, and malondialdehyde concentration (MDA). This evidence concerns the gene GSR and Alzheimer disease.