Sexual dimorphism in angiotensin II-induced hypertension and vascular alterations

Sex differences in the degree of high blood pressure have been described in several forms of experimental animal models of hypertension. However, the influence of sex on angiotensin II-induced hypertension has not been studied. In the present study, we investigated and compared the effects of chronic angiotensin II treatment on blood pressure and vascular function in male and female rats. Chronic treatment with angiotensin II (0.7 mg/kg daily for 10 d) significantly raised arterial blood pressure in male but not female Sprague-Dawley rats; it upregulated the NAD(P)H oxidase gp67 phox subunit in the aorta of male but not female rats; and it exaggerated the vasoconstrictor responses to norepinephrine and serotonin in the mesenteric vascular bed (MVB) of male but not female rats. Vasodilator responses to acetylcholine (ACh) but not papaverine (PPV) or isoprenaline (ISO) were reduced in the MVB of angiotensin II-treated male but not female rats. ACh, but not PPV or ISO dilatory responses were potentiated in the MVB of angiotensin II-treated female rats. The present findings demonstrate that exogenous angiotensin II upregulates aortic NAD(P)H oxidase gp67 phox subunit, and induces hypertension and mesenteric vascular dysfunction only in male rats.