Aim: This study was design to describe the effect of 17β estradiol on the dose-dependent expression patterns of endothelial nitric oxide synthase (eNOS) and inducible NOS (iNOS) enzymes by Western blotting in ovariectomized rat uterus.

Materials and Methods: Female, three months old, ovariectomized, 40 Sprague–Dawley rats were used. Rats in the control group (n=10) received intramuscular injection of sesame oil once daily for 3 days, whereas rats in the experimental groups were treated with intramuscular injection of 17β estradiol 25 (n=10), 50 (n=10) and 100 (n=10) μg/rat/day. The rats were killed by cervical dislocation at 18^th hour after the last injection. Immediately after death, the uterine horns were removed. The presence of eNOS and iNOS enzymes in uterine samples were analysed by Western blot and the densitometry of each film were performed.

Results: It was observed that the application of 25, 50 and 100 μg/rat/day 17β estradiol increased the eNOS expression as compared to control group The relative density of eNOS expressions in 25 and 50 μg/rat/day 17β estradiol groups was higher than those in 100 μg/rat/day 17β estradiol group. Similarly to eNOS, 25 and 50 μg/rat/day 17β estradiol groups showed higher iNOS expression as compared to control and 100 μg/rat/day 17β estradiol groups.

Conclusion: Estrogen may mediate the NOS/NO activity in ovariectomized rat uterus.