The study will be conducted in the Gila River Indian Community and include proteinuric subjects selected from the Diabetic Renal Disease Study (DRDS; NIH Protocol Number 88-DK-79) in whom glomerular function has been measured at six-monthly intervals for the past 48 months. Twenty-five subjects (12 men, 13 women) aged 31-64 years are eligible for this study. These subjects all have urinary albumin-to-creatinine rations >=300 mg/g (equivalent to 300 mg albumin/day), serum creatinine concentrations < 3.0 mg/dl, and no evidence of nondiabetic renal diseases. Their GFR slopes average -0.49 ml/min/month (95% confidence interval, -0.91 to -0.07), and 11 of them (8 men, 3 women) are hypertensive (systolic blood pressure >=140 mm Hg, diastolic blood pressure >=90 mm Hg).