Hormonal replacement therapy (HRT) has failed to provide a cardioprotective action in postmenopausal women, and thus alternative pharmacological approaches are required. The present study examined the therapeutic potential of the partial estrogen receptor agonist tamoxifen and the angiotensin II type-1 receptor antagonist irbesartan on the hemodynamic profile of ovariectomized (OVX) female SpragueDawley rats (911 weeks). Three weeks following ovariectomy, uterine atrophy was evident and body weight was increased as compared with sham-operated animals. Left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), and mean arterial pressure (MAP) were significantly increased in the OVX rats as compared with sham rats. One week following ovariectomy, rats were treated with either tamoxifen (10 mg kg1 day1) or irbesartan (40 mg kg1 day1) for a period of 2 weeks. The administration of tamoxifen to OVX rats partially reversed uterine atrophy and prevented body weight gain, albeit body weight remained significantly lower than in sham-operated animals. LVSP and LVEDP were normalized in the tamoxifen-treated OVX rats, whereas MAP remained elevated. Irbesartan partially reduced the body weight gain of the OVX rats and did not influence uterine atrophy. LVSP and MAP were normalized in irbesartan-treated OVX rats, whereas LVEDP remained elevated. These data demonstrate that irbesartan rather than tamoxifen was efficacious in normalizing MAP in the OVX rats without a secondary effect on the uterus.Key words: ovariectomy, hemodynamics, tamoxifen, AT1 receptor antagonists.
Effects of Angiotensin II Type 1 Receptor Antagonist, YM358, on Cardiac Hypertrophy and Dysfunction after Myocardial Infarction in Rats