PATHOPHYSIOLOGICAL SIGNIFICANCE OF PLASMA TOTAL RENIN AND PRORENIN INPATIENTS WITH DIABETES-MELLITUS

To seek the pathophysiologic significance of measuring the concentrati on of total renin instead of prorenin, we determined the plasma total renin concentration by immunoradiometric assay and correlated the resu lts with various clinical features and laboratory parameters of diabet ic complication in 108 patients with diabetes mellitus. The plasma pro renin concentration was estimated as the difference between the total and active renin concentrations. The plasma total renin and prorenin c oncentrations were high in patients with diabetes mellitus, in contras t to the active renin concentration which was slightly decreased. In a ddition, the plasma total renin and prorenin concentrations were highe r in patients with diabetic complications than in patients without any complication. Multiple regression analysis showed that the presence o f orthostatic hypotension, diabetic retinopathy, and proteinuria is si gnificantly associated with the increased plasma total renin and prore nin concentrations. In addition, there was a significant positive corr elation between the total renin and prorenin concentrations. These res ults suggest that both the plasma total renin concentration and the pr orenin concentration are closely related to diabetic complications. De termination of the plasma total renin concentration by immunoradiometr ic assay as a substitute for prorenin could be a powerful tool in eluc idating the mechanism for the increased plasma prorenin in diabetes me llitus.