Arterial Pressure, Plasma Renin Activity, Atrial Natriuretic Factor, and Sodium Excretion During Induced Hyper- and Hypoinsulinemia in Therapy-Resistant Hypertensives

Abstract

We investigated whether short-term changes in serum insulin would effect a reduction of arterial pressure in subjects with therapy-resistant essential hypertension. Six patients were examined twice with a 3 week's interval in a single-blind cross-over design with euglycemic insulin clamps (A and B). A reduction of endogenous serum insulin was achieved by continuous infusion of 50 microgram octreoid (a somatostatin analogue) per hour. During clamp A low dose insulin infusion (5 mU/m²/min) was given, whereas during clamp B insulin was infused at a rate of 60 mU/m²/min. Preceding each clamp a standard drug therapy was given for one week (50 mg atenolol +30 mg furosemide per day). During clamp A plasma insulin was reduced from 21.4 ± 7.5 to 10.8 ± 1.2 mU/l (p < 0.01) whereas plasma insulin rose during clamp B from 20.0 ± 7.5 to 99.0 ± 17.2 mU/l (p < 0.001). The mean arterial blood pressure did not decrease during clamp A (low dose insulin infusion). There was an increased natriuresis during the high-insulin clamp (70 vs. 38 mmol, p = 0.13), but no difference in arterial pressure between the clamps.

Key Words:

• Essential hypertension/drug therapy
• natriuresis
• insulin
• somatostatin
• euglycemic clamp test
• ANF