[Plasma renin and catecholamine activity in pheochromocytoma].

We have studied the renin aldosterone system and plasma catecholamines in 26 untreated patients with phaeochromocytoma, 21 untreated patients with primary hypertension, and in 10 normal volunteers. Blood pressure (mmHg), plasma renin activity (radioimmunoassay of angiotensin I, ng/ml/h), plasma concentrations of aldosterone (direct radioimmuno-assay, pg/ml), adrenaline and noradrenaline (radioenzymatic assay with catechol-O-methyl transferase, pg/ml) were measured after 1 h of supine rest, 5 mn upright and after walking 1 h. Seven patients with phaeochromocytoma were subsequently given 400 mg acebutolol bid for 3 days, and five were given 1 mg/kg captopril. Supine renin activity was higher in phaeochromocytoma than in primary hypertension and in volunteers (average 2.54, 1.03 and 0.85, F = 7.1, p less than .01) and rose higher after walking (mean increase 3.84, 1.19 and 0.68 respectively, F = 6.3, p less than .01). Aldosterone was higher after walking in phaeochromocytoma than in primary hypertension (534 vs 275 pg/ml, p = .03). Differences in renin and aldosterone could not be explained by age, natriuresis or plasma volume. Catecholamines were as expected much higher in phaeochromocytoma than in the other two groups (p less than .01). At variance with primary hypertensive and normal volunteers, renin was tightly correlated with noradrenaline in patients with phaeochromocytoma (r' = .54, r' = .60, and r' = .74 in supine position, after standing and after walking 1 h, p less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)