The relationship between potassium balance and circulating catecholamines in essential hypertension

Abstract

A study of neuroendocrine trend and electrolytes balance was carried out in 29 patients with essential hypertension and 20 normotensive controls. Based on plasma norepinephrine (NE) resting values to subgroups of hypertensives were defined, one in the "normal" range (NE less than 268 pg/ml) and one in the "high" range (NE greater than 268 pg/ml). In response to graded exercise the "high" NE hypertensive patients showed a mean NE increase significantly higher than both normal controls and "normal" NE hypertensives (p less than 0.05). No significant differences in the electrolytes excretion rates were found between the two subsets, but only in the hyper-noradrenergic hypertensives a negative correlation between potassium excretion and circulating NE levels was observed (r = -0.68; p less than 0.005). These findings suggest that in the hypertensive population there is a not negligible proportion of patients with elevated NE levels under basal conditions which are, moreover, hyper-responsive to stressful situations. This abnormal sympathetic function could be probably related to the state of potassium balance.