Racial analysis of the volume-renin relationship in human hypertension

We studied 29 normotensive men (14 black, 15 white) and 36 hypertensive men (27 white, nine black) to examine the association of race with blood pressure, blood volume, and peripheral renin activity (pra). Blood volume was lower in white hypertensive men than in white normotensive men, but was similar in all blacks. When subjects were tested in the supine position, PRA was lower in black normotensive subjects than white normotensive subjects. The PRA did not differ among groups tested in an upright posture, while furosemide-stimulated PRA was lower in hypertensive than normotensive subjects of both races despite lower blood volumes in white hypertensive subjects. Differences of volume and renin measurements appear to reflect basic differences between whites and blacks with essential hypertension. We emphasize the need to consider race in the investigation of human hypertension.