اثر تنظيمي هورمون هاي استروييدي تخمداني بر توليد اكسيدنيتريك در موش صحرايي

The Regulatory Effect of Ovarian Steroid Hormones on Nitric Oxide Production in Female Rat

Background: Nitric oxide (NO) is a molecule that plays a role in many biological processes. Body NO production is regulated by multifactorial mechanisms and the steroid hormones seem to have a role in this process. The role of estrogen and progesterone on NO production was not fully understood, therefore the aim of this study was to detect the effect of ovarian steroid hormones on NO production in ovarectomized adult female rats. Materials and Methods: 120 female rats were ovarectomized bilaterally and divided into 3 main groups 14 days after the surgery: Estrogen group received estradiol benzoate subcutaneously (10miug/kg), progesterone group received progesterone (25 mg/kg) subcutaneously and last group received both hormones as above. In each main group, the subgroups received L-NAME (60 mg/kg), L-Arginine (100 mg/kg) or vehicle intraperitoneally. After treatment blood samples were collected and serums nitrite and nitrate were measured using griess reaction method. Results: The serum nitrite and nitrate were decreased when progesterone was administered (stable metabolites of NO). This effect blocked with L-Arginine but enhanced with L-NAME. The administration of estradiol increased serum nitrite and nitrate, but this effect was inhibited by L-NAME. Injection of both hormones did not show any significant effects on nitrite and nitrate levels of serum. L-NAME decreased the serum nitrite and nitrate concentration, but L-Arginine increased them. Conclusion: Considering these data, it can be suggested that, ovarian steroid hormones have an affect on ragulation of NO production. The effect of sex steroid hormones on target tissues may be mediated by NO system.