Hyperinsulinemia Is Not a Cause of Cortisol-Induced Hypertension

Abstract

There is much interest in the relationship of hypertension to hyperinsulinemia. Six male volunteers received cortisol, 50 mg orally four times daily, for 5 days. Plasma insulin concentration increased from 11.8 +/- 3.0 mU/L to 16.1 +/- 4.0 mU/L (P = .034). Fasting glucose increased from 4.7 +/- 0.3 to 5.8 +/- 0.1 mmol/L (P = .001). The insulin-to-glucose ratio was unchanged. Octreotide has been reported to lower blood pressure in obese, hyperinsulinemic, hypertensive patients. The hypothesis that cortisol-induced hypertension might be secondary to steroid-induced hyperinsulinemia was examined by determining whether reversal of hyperinsulinemia by octreotide would reverse cortisol-induced hypertension. Five healthy men were given two subcutaneous injections of 0.05 mg of octreotide before and on the fifth day of cortisol administration. Cortisol increased blood pressure, weight, plasma glucose concentration, and white cell count, with decreases in plasma potassium concentration and packed cell volume. Plasma cortisol concentrations were unchanged following octreotide in the control period but decreased after cortisol treatment. Insulin concentrations were reduced profoundly after octreotide, both in the control period (12.5 +/- 3.7 mU/L, falling to 1.1 +/- 0.3 mU/L at 30 min) and on cortisol (22.3 +/- 4.5 to 2.3 +/- 0.5 mU/L at 30 min). Octreotide did not lower pressure before or after cortisol treatment. Thus, octreotide was effective in lowering plasma insulin concentrations but di not lower blood pressure in normal subjects with cortisol-induced hypertension. These data do not support the notion that steroid-induced hyperinsulinemia is responsible for steroid-induced hypertension.