Racial differences in endothelin-1 at rest and in response to acute stressin adolescent males

Blacks exhibit greater vasoconstriction-mediated blood pressure (BP) increa ses in response to stress than do whites. Endothelin-1 (ET-1), a potent vas oconstrictive peptide, has been proposed as having a role in racial differe nces in stress reactivity, We evaluated the hemodynamic and plasma ET-1 lev els of 41 (23 whites, 18 blacks, mean age 18.6 years) normotensive adolesce nt males at rest and in response to a video game challenge and forehead col d stimulation. Measurements were performed at catheter insertion and before and immediately after the 2 stressors, which were separated by 20-minute r est periods. Blacks exhibited higher absolute levels of diastolic blood pre ssure, total peripheral resistance index, or both in response to catheter i nsertion and to the video game challenge and during recovery from video gam e challenge and cold stimulation (P<0.05 for all). Blacks exhibited higher absolute levels of ET-1 at every evaluation point (P<0.05 for all) and grea ter increases in ET-1 in response to both stressors (ps<0.05). These findin gs suggest that altered endothelial function may be involved in racial diff erences in hemodynamic reactivity to stress and possibly in the development of essential hypertension.