Racial differences in plasma endothelin-1 concentrations in individuals with essential hypertension.

Hypertension is more prevalent in blacks than whites, and the reasons for this difference remain unclear. To test whether endothelin may play a role in these racial variations, we analyzed plasma samples from black and white women and men with high blood pressure by an enzyme-linked immunoassay specific for endothelin-1 (ET-1), a potent vasoconstrictor, and compared them with those obtained from similar subjects with normal blood pressure. Both female and male hypertensive blacks had elevated levels of immunoreactive ET-1 (11.3 +/- 1.0 and 12.3 +/- 1.3 pmol/L, respectively) compared with values in normotensive control blacks (1.5 +/- 0.2 and 1.4 +/- 0.2 pmol/L). Corresponding values in female and male hypertensive whites were 3.8 +/- 0.6 and 3.8 +/- 0.6 pmol/L, respectively, compared with respective values of 1.4 +/- 0.1 and 2.8 +/- 0.4 pmol/L in normotensive control whites. These results indicate that plasma concentrations of immunoreactive ET-1 levels differ significantly between black and white individuals with high blood pressure. This finding may be an important factor in the etiology of racial differences in the prevalence and severity of hypertension and deserves further study [corrected].