The discovery and isolation of insulin earlier in this century proved a life-saving advance for many diabetics. But with this treatment new challenges emerged鈥攖he progressive systemic microvascular and macrovascular injuries that limit both the quality and duration of life of these patients.1 Therefore, much attention has turned to the prevention, early diagnosis, and therapy of these vascular complications. One of these, diabetic nephropathy, while affecting only a minority of diabetics, is particularly devastating, for, while treatment exists, no cure is known. At end stage, these diabetics must undergo renal-replacement therapy with either dialysis, and its attendant intrusions on life-style and medical complications, or renal transplantation, also a lessthan-perfect remedy. Of the diverse causes of end-stage renal disease (ESRD), diabetes represents the fastest expanding subgroup. By 1988, 34% of individuals reaching ESRD in the United States were diabetic, in contrast with 21% of individuals 6 years earlier (P. Eggers, oral