ABSTRACT
PURPOSE: To investigate involvement of chronic estrogen deficiency in impairment of relaxation response of the clitoral cavernous smooth muscle. MATERIALS AND METHODS: New Zealand white female rabbits were randomly divided control (sham operation, n=6) and experimental groups; 1) bilateral oophorectomy (n=8), 2) oophorectomy with estradiol replacement (n=7), 3) oophorectomy with flutamide treatment (n=6). All the rabbits were sacrificed 12 weeks after the operations. Blood levels of estradiol and lipid fractions were measured just before the operations and sacrifice. Clitoral cavernous strips were obtained to observe relaxation responses to endothelium-dependent and -independent vasodilators, and electrical field stimulation (ESF). RESULTS: The uterus weight and serum estradiol level decreased significantly (p<0.01) in the oophorectomy group compared with the baseline data. The serum levels of total cholesterol, triglyceride, and low density lipoprotein increased significantly (p<0.01) in the oophorectomy group. The relaxations of the clitoral strips to acetylcholine were significantly attenuated in the oophorectomy group compared with those of the control and estrogen replacement groups. However, sodium nitroprusside- and nonadrenergic noncholinergic-induced relaxations were not significantly different among the 4 groups. No significant histologic changes were noted in the clitoral tissues of the oophorectomy group. CONCLUSIONS: Chronic estrogen deficiency in the rabbits may cause impairment of endothelium-dependent relaxation of clitoral corpus cavernosal smooth muscles. Further studies are needed to determine whether the hypoesterogenemia itself and/or secondary hypercholesterolemia due to the chronic estrogen deficiency may result in the impairment.