The modulatory effect of estradiol benzoate on superoxide dismutase activity in the developing rat brain

Abstract

The sensitivity of copper,zinc (CuZn)-and manganese (Mn)-superoxide dismutase (SOD) to exogenous estradiol benzoate (EB) was investigated in Wistar rats during postnatal brain development. Enzyme activities were measured in samples prepared from brains of rats of both sexes and various ages between 0 and 75 days, treated sc with 0.5 µg EB/100 g body weight in 0.1 ml olive oil/100 g body weight, 48 and 24 h before sacrifice. In females, EB treatment stimulated MnSOD activity on days 0 (66.1%), 8 (72.7%) and 15 (81.7%). In males, the stimulatory effect of EB on MnSOD activity on day 0 (113.6%) disappeared on day 8 and on days 15 and 45 it became inhibitory (40.3 and 30.5%, respectively). EB had no effect on the other age groups. The stimulatory effect of EB on CuZnSOD activity in newborn females (51.8%) changed to an inhibitory effect on day 8 (38.4%) and disappeared by day 45 when inhibition was detected again (48.7%). In males, the inhibitory effect on this enzyme was observed on days 0 (45.0%) and 15 (28.9%), and then disappeared until day 60 when a stimulatory effect was observed (38.4%). EB treatment had no effect on the other age groups. The sensitivity of MnSOD to estradiol differed significantly between sexes during the neonatal and prepubertal period, whereas it followed a similar pattern thereafter. The sensitivity of CuZnSOD to estradiol differed significantly between sexes during most of the study period. Regression analysis showed that the sensitivity of MnSOD to this estrogen tended to decrease similarly in both sexes, whereas the sensitivity of CuZnSOD showed a significantly different opposite tendency in female and male rats. These are the first reports indicating hormonal modulation of antioxidant enzyme activities related to the developmental process. Correspondence

The role of interleukin‐1b and its antagonist (diacerein) in estradiol benzoate‐induced endometrial hyperplasia and atypia in female rats

“…That is due to accumulation of highly reactive free radicals, which led to significant reduction in SOD activity. That is in agreement with Pejić et al .…”

“…Cells develop an enzymatic antioxidant pathway against reactive oxygen species, which are generated in oxidative metabolism. SOD catalyses the superoxide anion (O 2 ˙ − ) to hydrogen peroxide (H 2 O 2 ), which in the second step is converted to water by catalase or GSH .…”

“… Group I was received vehicle of DIA (1% carboxymethylcellulose) and intramuscular (im) olive oil three times per week for 4 weeks . Group II was treated with DIA (50 mg/kg/day orally) and im olive oil 3 times per week for 4 weeks . Group III was treated with vehicle of DIA (1% carboxymethylcellulose) and im injection of EB (60 μg/100 g) three times per week for 4 weeks . Group IV was treated with DIA (50 mg/kg/day orally) + im injection of EB (60 μg/100 g) three times per week for 4 weeks . …”

EstradiolIn VivoRegulation of Brain Mitochondrial Proteome

“…Increased expression of peroxiredoxin-V is consistent with the well documented antioxidant effects of estrogens (Behl et al, 1995;Ejima et al, 1999;Urata et al, 2006), including increased glutaredoxin expression (Ejima et al, 1999;Diwakar et al, 2006;Urata et al, 2006). In contrast to the reported E 2 -induced increase in expression of MnSOD (Pejic et al, 2003;Strehlow et al, 2003), we did not observe significant changes in the MnSOD protein spot identified in the current 2D proteomic analysis. This may be because of multiple distributions within the gel caused by posttranslational modifications or to selective regulation by E 2 during brain devel- Figure 5.…”

“…C, Whole-brain mitochondria from control and E 2 -treated rats were assessed for protein expression by Western blot analysis (n ϭ 4; *p Ͻ 0.05 compared with control). opment (Pejic et al, 2003) or selective E 2 regulation within the vasculature (Strehlow et al, 2003). Selective regulation of different antioxidant proteins could indicate protection against different oxidative stresses.…”