Plasma renin and aldosterone in adult-onset diabetics with persistent proteinuria

Plasma renin activity (PRA) and plasma aldosterone (PA) were measured under conditions of bed rest and after administration of furosemide and/or angiotensin II to adult-onset diabetics and age-matched controls. Seventeen of the diabetics had no proteinuria (non-proteinuria group) while in the other ten subjects, there was a persistent proteinuria, but no hypertension and renal dysfunction (proteinuria group). In the non-proteinuria group, changes in PRA and PA levels during both bed rest time and after the stimulation with furosemide did not significantly differ from findings in the control group. In the proteinuria group, PRA and PA levels were significantly lower than in the other two groups. PA and diastolic pressure responses to angiotensin II were slightly increased in diabetics (N.S.). PA responses to furosemide had significant positive correlation with those to angiotensin II. These findings suggest that the renin-aldosterone system responds normally in adult onset diabetics without proteinuria, but shows lower response in diabetics with persistent proteinuria, even without complications of hypertension and a decreased renal function.