Changes in the excretion of catecholamines and their metabolites in patients with essential hypertension during sodium intake restriction.

Excretion of noradrenaline (NA), adrenaline (A), dopamine (DA) and their metabolites vanillylmandelic acid (VMA), methoxycatecholamines (MNA + MA) as well as 3-methoxy-4-hydroxy-phenylglycol (MHPG) was studied in 95 patients with essential hypertension and in 25 normal subjects on normal and low sodium diets. The patients were divided into 3 groups according to NA excretion under basal conditions. NA excretion was increased during sodium intake restriction, the highest values of this increase being found in patients whose basal NA excretion was diminished. At low sodium intake the high and the low NA excretors responded with significant increases of DA excretion. The mean excretion of VMA increased significantly on low sodium diet in all 3 groups of patients. The MNA + MA excretion decreased significantly during sodium intake restriction in patients with normal NA excretion. At low sodium intake the excretion of MHPG was highest in patients with low basal NA excretion. These data suggest that in patients with essential hypertension subjected to sodium restriction the excretion and metabolism of catecholamines are related to basal sympathetic activity.