Role of Insulin in the Pathogenesis of Hypertension Associated with Glucose Intolerance

Abstract

The role of insulin in the pathogenesis of hypertension was explored in normal men and male patients with impaired glucose-tolerance. They were classified as normal (n = 94), borderline (n = 164), impaired tolerance (IGT, n = 104), or diabetes mellitus (n = 100) according to their response to an oral 75g glucose challenge. Besides routine laboratory examinations, fasting immunoreactive insulin and post-glucose insulin levels at 30 minutes were measured. Patients with impaired glucose tolerance were older and more obese than the normal subjects. Serum cholesterol and triglyceride concentrations increased with severity of the glucose tolerance impairment. However, renal function, as estimated by blood urea nitrogen levels did not differ among these four groups. Multiple regression analysis revealed that blood pressure correlates significantly with the obesity index, blood glucose, serum cholesterol and serum insulin in all four groups. Among these groups, the partial F ratios for the obesity index were the greatest in both normal and diabetic groups, but in both borderline and IGT groups those for insulin were the greatest. These results indicate that in patients with impaired glucose tolerance is hypertension associated more closely with hyperinsulinemia than it is in normal subjects or diabetic patients.