Urinary Excretion of Catecholamine Derivatives in Essential Hypertension

Abstract

Urinary excretion of norepinephrine (NE), epinephrine (E), normetanephrine (NMN), metanephrine (MN) and vanillyl mandelic acid (VMA) were measured in 10 hypertensive and 10 normotensive subjects at walking and in sleep. No difference in urinary excretion of each of NE, E, NMN, MN and VMA was observed in sleep between the hypertensive and normotensive subjects. Urinary excretions of NE, E, NMN, MN and VMA at walking were 3 to 6 times higher than those in sleep in both groups. The rate of increase in catecholamine excretion at walking was higher in the hypertensive subjects. At walking, urinary excretion of VMA in the hypertensive group was significantly higher. The ratio of VMA to total catecholamine was lower at walking.Elevated urinary catecholamine excretion in the hypertensive suggests that the substance plays a role as a causative factor of hypertension.Studies of hypertension induced by endogenous substances have been carried out with special attention to the adrenal medulla. However, the results of urinary excretion of catecholamines and their metabolites in essential hypertension have been controversial.It is well established that excretion of catecholamines is increased under various conditions such as upright posture,1 exercise2 and emotional tension.3 Consequently, a proper comparison is possible only when the effects of such conditions are minimized at the measurement.The present study was made to determine whether or not there are any dif ferences in excretion of catecholamines between patients with essential hyperten sion and normal subjects by measuring the urinary output of norepinephrine (NE), epinephrine (E), normetanephrine (NMN), metanephrine (MN) and vanillyl mandelic acid (VMA) in sleep and at walking. MATERIALS AND METHODSUrinary excretion of NE and E, conjugated NMN and MN, and VMA at walk ing and in sleep was measured in 10 hypertensive subjects aged 20 to 47 years (averaging 37 years) with systolic blood pressure over 150mm Hg and/or diastolic