Expression of α1 Receptor and Nitric Oxide Synthase in Oophorectomized and Estrogen-Supplemented Rat Bladder and Urethra

PURPOSE To investigate the effects of estrogen on the expression of the α1 receptor and nitric oxide synthase (NOS) in rat urethra and bladder after oophorectomy. MATERIALS AND METHODS Forty-five mature female Sprague-Dawley rats (aged 10-11 weeks, 235-250 g) were randomly assigned to one of three groups: control group, oophorectomy group (Opx), or oophorectomy and estradiol replacement group (Opx+ Est). The degree of expression of α1 receptor (α1A and D) and NOS (neuronal NOS [nNOS] and endothelial NOS [eNOS]) in bladder and urethral tissues was investigated by using immunohistochemical staining and Western blotting. RESULTS In the bladder, the expression rates of α1 receptor (α1A and α1D) increased in the Opx group but decreased in the Opx+Est group. These changes were not statistically significant. The α1A and α1D receptor of the urethra decreased in the Opx group but increased in the Opx+Est group. These changes were not statistically significant. In the bladder and urethra, the expression rates of nNOS and eNOS significantly increased in the Opx group but decreased in the Opx+Est group (p<0.05). CONCLUSIONS These data suggest that estrogen depletion increases NOS and α1 receptor expression in the rat bladder. However, these changes could be restored by estrogen replacement therapy.