Hypertension, Vol 17, 546-552, Copyright © 1991 by American Heart Association
Plasma norepinephrine and dihydroxyphenylglycol in essential hypertension
J Ludwig, M Gerlich, T Halbrugge and KH Graefe
Medizinische Poliklinik, University of Wurzburg, FRG.
The aim of the present study was to examine whether essential hypertension
is associated with altered plasma concentrations of dihydroxyphenylglycol,
the principal presynaptic metabolite of norepinephrine. Forearm venous
plasma dihydroxyphenylglycol and norepinephrine were determined at rest and
during graded orthostasis in 47 normotensive control subjects and 58
outpatients with essential hypertension. There was no group difference in
age. At supine rest as well as during sitting and standing, hypertensive
subjects had plasma norepinephrine concentrations similar to those in
normotensive control subjects, but plasma dihydroxyphenylglycol
concentrations were higher than those in normotensive control subjects.
Both groups showed a linear relation between plasma dihydroxyphenylglycol
(ordinate) and plasma norepinephrine (abscissa). The resulting regression
line was steeper (p less than 0.02) and its ordinate intercept higher (p
less than 0.01) in hypertensive than in control subjects. Eleven
normotensive and 14 hypertensive subjects were also tested 3 hours after
desipramine (1.5 mg/kg orally) was administered to inhibit neuronal
norepinephrine reuptake. The drug did not alter plasma norepinephrine, but
did reduce plasma dihydroxyphenylglycol and did abolish plasma
dihydroxyphenylglycol responses to upright posture in both groups of
subjects. The mean plasma dihydroxyphenylglycol concentration observed in
the presence of desipramine again was higher in the hypertensive than in
the control group (p less than 0.01) and closely agreed, in both groups,
with the dihydroxyphenylglycol concentration given by the ordinate
intercept of the dihydroxyphenylglycol versus norepinephrine regression
line in the absence of desipramine.(ABSTRACT TRUNCATED AT 250 WORDS)