In this study of the effect of ovariectomy, increases in MDA make the determination that uterine oxidative stress is increased.

4. Gomez-Zubeldia, M. A.; Arbues, J.; Corrales, S.; Millan, J. C.; Nogales, A. G.
JOURNAL NAME- Gynecologic Oncology VOL. 86 NO.  3 September, 2002 PP. 250-258.
DOCUMENT TYPE- Article ISSN- 0090-8258
ADDRESS- School  of Medicine, University  of  Extremadura  , Avenida Elvas s/n., 06071, Badajoz  ,  Spain 
LANGUAGE- ENGLISH
Objective. We studied the effect of ovariectomy, estradiol (E2), and E2 + medroxyprogesterone (MPA) on the Wistar rat uterus. Methods. We used 15 adult female rats. The study was divided into the following four stages: (a) extirpation of the upper half of the left hemi-uterus (basal state) and ovariectomy; (b) animals were maintained for 15 days without treatment, performance of a new laparotomy, and extirpation of the remaining left hemi-uterus (OVX state); (c) beginning of E2 replacement therapy (ERT) (8 mug/day) for 15 days, followed by extirpation of the upper half of the right hemi-uterus (ERT state); and (d) the administration of E2 was continued, and oral treatment with MPA was begun (20 mug/day) to last for a further 15 days. At the end of the combined hormone replacement therapy (HRT) the remaining right hemi-uterus was extirpated (HRT state). At the end of each intervention, the plasma concentrations of E2 and PRG were measured. Results and Discussion. The ovariectomy significantly reduced the malondialdehyde ( MDA ) levels (P < 0.0008) and catalase activity (P < 0.0006). The ERT very significantly (P < 0.0033) raised the catalase and MDA levels ; these significance levels were maintained after the Bonferroni method was applied (overall error 5%). The HRT reduced the levels of MDA and catalase, but not significantly after the Bonferroni test was applied. Conclusions. Uterine oxidative stress is increased by E2, resulting in a significant increase in MDA. This may be modulated in part by the catalase activity. Although it cannot be confirmed categorically, MPA seems to intervene by decreasing the said oxidative stress.

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