Integrated concentration of epinephrine and norepinephrine in normal subjects and in patients with mild essential hypertension.

Since the level of plasma catecholamines fluctuates rapidly during the day, measurement in a single blood sample could be misleading. A portable nonthrombogenic blood withdrawal system, permitting normal activity and sleep, was used for obtaining the 24-h integrated concentration (IC) of epinephrine (E) and norepinephrine (NE) in 46 normal control subjects, 30 patients with mild essential hypertension, and 1 patient with pheochromocytoma. The mean IC of E (ICE) and the mean IC of NE (ICNE) of the control subjects were 31 +/- 15 and 194 +/- 106 pg/ml, respectively (mean +/- 1 SD). The mean ICE and ICNE of the essential hypertensive patients were 30 +/- 21 and 224 +/- 90 pg/ml, respectively. No significant difference could be found between the levels found in essential hypertensive and normal control subjects. The levels of ICE and ICNE in the patient with pheochromocytoma were 1350 and 882 pg/ml, respectively, which are 88 and 6.5 SD above the mean of the normal control subjects.