Effects of progesterone and estradiol benzoate on glutathione dependent antioxidant enzyme activities in the brain of female rats

The activities of glutathione dependent antioxidant enzymes were measured i n subcellular fractions of whole brain homogenates prepared from ovariectom ized (OVX) female rats, untreated or treated 2 h or 24 h prior to sacrifice with a single dose of 2 mg progesterone (P) or 5 mu g estradiol benzoate ( EB). Glutathione peroxidase (GSH-Px) activity was not changed following sys temic administration of EB, but P increased GSH-Px in the brain of OVX rats 24 h after the treatment. The activity of glutathione reductase (GR) was s uppressed by EB short time, only 2 h following treatment, whereas P increas ed the enzyme activity 24 h after treatment. On the other hand, the activit ies of catalase (CAT) and glutathione-S-transferase (GST) were not changed following systemic administration of EB or P. The present work was carried out to study the involvement of ovarian steroids, especially P, in the cont rol of GSH-Px and GR activities, and our results suggest that oxidative str ess in the brain of female rats may be modulated by the level of progestero ne.