The effects of race on norepinephrine clearance

Abstract

Eighteen normotensive and 19 unmedicated hypertensive black and white male subjects were studied twice, during a 10 meq sodium diet for 5 days and a 200 meq sodium diet for 4 days. The subjects received an infusion of 3H-norepinephrine ( 3HNE) during both low and high sodium diets to measure NE clearance. Dietary sodium and blood pressure classification had no effect on 3HNE clearance. Infusion of pressor doses of NE also failed to alter 3HNE clearance. Both normotensive and hypertensive blacks had increased 3HNE clearance rates (p < .001). The increased rate of 3HNE clearance among blacks was not affected by alterations in dietary sodium or by pressor doses of NE. Increased NE clearance by blacks may help explain obser-vations that white hypertensives in the age range we studied (25–46 years) have elevated plasma NE levels, while blacks have normal NE levels.