Objective To observe the effect of
estrogen replacment therapy on expression of arterial estrogen redioligand (ER) and
vascular endothelial NOS activity.Methods The female rats were given ovariectomy with or without estrogen replacement therapy.The radioligand binding assay was adopted to measure the estrogen receptors in the aorta of the rat.The NOS activity in aorta was assessed by method of hemoglobin reductase.Results The ER binding capacity and NOS activity in the
arteries of
ovariectomized group were lower than those in sham operation group(P<0.05).The ER binding capacity and NOS activity in the arteries of estrogen replacement therapy group were higher than those in ovariectomized group(P<0.05).No significant difference in the ER Kd value were observed between the three groups.Conclusions The ER number and NOS activity in the aorta of rat significantly decrease after ovariectomy,while estrogen replacement therapy can significantly increase the arterial NOS activity and maintain the ER number in the arteries of ovariectomized rat at normal level.The result may contribute to explaining the beneficial effect of estrogen on the prevention of coronary artery diseases in postmenopausal women.