Urinary norepinephrine and epinephrine excretion rates are heritable, but not associated with office and ambulatory blood pressure

Genetic and environmental contributions to urinary excretion rates of norepinephrine (UNEV) and epinephrine (UEV) and their association with blood pressure (BP) were investigated in 91 African American (mean age, 17.3 +/- 2.6 years) and 101 European American (mean age, 18.7 +/- 3.4 years) mono- and di-zygotic twins. Genetic modeling was performed using Mx software. UNEV (1.9 +/- 1.3 mu g h(-1)) and UEV (0.2 +/- 0.2 mu g h(-1)) were highly correlated (r = 0.81, P < 0.001). Significant heritabilities for UNEV (0.68) and UEV (0.74) without ethnic and gender effects were observed. The genetic correlation between UNEV and UEV was 0.86. There was no clear pattern of correlations for UNEV and UEV with BP measures in European Americans, but African Americans showed some inverse correlations of moderate size. Measurements of UNEV and UEV provide a viable method for the study of sympathetic tone and are substantially heritable. Hypertension Research (2012) 35, 1164-1170; doi:10.1038/hr.2012.104; published online 12 July 2012