Abstract-Red wine polyphenols (RWPs) have been reported to prevent hypertension and endothelial dysfunction.Several individual RWPs exert estrogenic effects. We analyzed the possible in vivo protective effects on blood pressure and endothelial function of RWPs in female spontaneously hypertensive rats (SHR) and its relationship with ovarian function. RWPs (40 mg/kg by gavage) were orally administered for 5 weeks. Ovariectomized rats showed both increased isoprostaglandin F 2␣ excretion and aortic superoxide production and reduced relaxant response to acetylcholine and contraction to the endothelial nitric oxide synthase (eNOS) inhibitor L-NAME measured in the aorta but similar blood pressure, as compared with sham-operated rats. Moreover, in ovariectomized rats aortic eNOS expression was unchanged, whereas caveolin-1, angiotensin II receptor (AT)-1, and the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits p22 phox and p47 phox expression was increased compared with sham-operated rats. In both ovariectomized and sham-operated SHR, RWPs reduced systolic blood pressure, urinary isoprostaglandin F 2␣ excretion, and aortic O 2 Ϫ production, improving the endothelium-dependent relaxant response to acetylcholine in SHR. These changes were associated with unchanged aortic eNOS expression, whereas caveolin-1 was increased and the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits p22 phox and p47 phox expression was reduced. RWPs had no effect on the AT-1 overexpression found in ovariectomized animals. All these results suggest that a chronic treatment with RWPs reduces hypertension and vascular dysfunction through reduction in vascular oxidative stress in female SHR in a manner independent of the ovarian function. Key Words: red wine polyphenols Ⅲ spontaneously hypertensive rat Ⅲ endothelial dysfunction Ⅲ NADPH oxidase Ⅲ ovariectomy T he incidence of cardiovascular diseases among premenopausal women is lower than age-matched, men but it rises markedly after menopause. Blood pressure is also higher in men than in women at similar ages, 1 and this difference is also reduced or even inverted after menopause. The loss of estrogens has been suggested as a major risk factor for postmenopausal hypertension. Estrogen receptor (ER) subtypes ER␣ and ER are expressed in endothelial and smooth muscle cells. [2][3][4][5] Estrogens increase endothelial-derived NO, modulate the local tissue reninangiotensin system, and show antioxidant effects. [3][4][5][6][7][8][9][10] Long-term estrogen treatment improves endothelial dysfunction, through upregulation of endothelial nitric oxide synthase (eNOS), 11,12 posttranslational modulation of eNOS activity, 13 or nongenomic effects, including activation of NO synthesis. 14,15 However, despite the positive effects on vascular function found in cell culture, 12,14 ex vivo 15 and in vivo animal 16 -18 and short-term human 7,19 -21 studies, estrogen replacement therapy has failed to protect from cardiovascular diseases in large scale randomized controlled ...