Adrenal response to angiotensin II in black hypertension lack of sexual dimorphism

Adrenal responsiveness to angiotensin (Ang) II is markedly blunted in black hypertensive patients compared with white hypertensive patients. One chara cteristic of this blunted adrenal response in whites is a powerful sexual d imorphism: premenopausal white women rarely show blunted responses. This ab normality, most evident when the system is activated by a low-salt diet, is a cardinal feature of the syndrome of nonmodulation, affecting a large per centage of white hypertensive patients. Nonmodulation is also marked by an increase in cardiovascular risk beyond that from hypertension itself. This study investigated whether young black women are likewise spared its expres sion or whether the adrenal unresponsiveness common among black hypertensiv e patients is unaccompanied by a gender bias. We compared the adrenal respo nse to Ang II in 382 hypertensive patients (313 white, 69 black; 238 male, 144 female). Ang II was infused when subjects were in balance on a 10-mmol Na+ intake. As anticipated, white hypertensive patients showed a very stron g sexual dimorphism, with women having twice the aldosterone response of me n (P=0.0001). Blacks, on the other hand, showed no gender difference (P=0.9 ). Increasing age had the dramatic effect of reducing responsiveness in whi te women but not in blacks. Young black women demonstrated the same bluntin g of adrenal responsiveness as older black women and black men of all ages. Mechanisms protecting against a blunted adrenal response to Ang II in youn g white women are absent in blacks. These differences may contribute to the markedly increased prevalence of hypertension in young black women.