Insulin Resistance and the Effect of Insulin on Blood Pressure in Essential Hypertension

• Published in: Hypertension (Dallas, Tex. 1979) Vol. 32; no. 2; pp. 243 - 248
• Main Authors: Heise, Tim, Magnusson, Kai, Heinemann, Lutz, Sawicki, Peter T.
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Heart Association, Inc 01.08.1998; Hagerstown, MD Lippincott
• Subjects: Administration, Cutaneous; Adult; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; Blood Pressure - drug effects; Cardiology. Vascular system; Clinical manifestations. Epidemiology. Investigative techniques. Etiology; Double-Blind Method; Female; Humans; Hypertension - drug therapy; Hypertension - physiopathology; Hypoglycemic Agents - administration & dosage; Insulin - administration & dosage; Insulin resistance; Insulin Resistance - physiology; Male; Medical sciences; Middle Aged; Vasodilation - drug effects; Endocrinopathy; Human; Hypertension; Pharmacologic test; Obesity; Pathophysiology; Nutrition disorder; Cardiovascular disease; Exploration; Glucose; Insulin; Uptake; Vasodilation; Target tissue resistance; Concomitant disease; Subcutaneous administration; Blood pressure; Nutritional status
• ISSN: 0194-911X; 1524-4563
• DOI: 10.1161/01.hyp.32.2.243

The aim of this study was to investigate the effect of 2 weeks of insulin administration on blood pressure and to simultaneously measure insulin sensitivity and insulin-induced vasodilatation in obese hypertensive patients. In a prospective, randomized, double-blind, crossover study (study 1), 23 obese, untreated, nondiabetic, hypertensive patients received either neutral protamine Hagedorn (NPH) insulin (0.3 U/kg body wt per day) or placebo subcutaneously for 2 weeks (washout period, 2 weeks). Office and 24-hour blood pressure values were measured at the beginning and end of each treatment period. In an open-label study (study 2), 8 obese hypertensive patients and 10 healthy control subjects underwent a 3-step hyperinsulinemic, euglycemic glucose clamp (step 1, 0.5; step 2, 2.5; step 3, 5.0 mU [middle dot] kg [middle dot] min [120 minutes each]). Leg blood flow (LBF) was measured by venous occlusion plethysmography. Insulin administration decreased mean +/- SD office blood pressure from 131 +/- 13 to 128 +/- 12 mm Hg (placebo, 132 +/- 13 and 132 +/- 13 mm Hg; P<0.05 between final examinations) and mean +/- SD 24-hour blood pressure by -3.3 +/- 6.9 mm Hg (placebo, +0.7 +/- 4.6 mm Hg; P<0.05). Insulin infusion increased LBF significantly in the healthy controls but not in obese insulin-resistant hypertensive subjects. Obese hypertensive patients are resistant to the effects of insulin with regard to both glucose uptake and vasodilatation. Administration of insulin exerts a small blood pressure-lowering effect in these patients. These data strongly argue against the postulated pressor action of insulin in essential hypertension. (Hypertension. 1998;32:243-248.)