Effects of nephrectomy and high-protein diets on glomerular hemodynamics and urinary protein excretion in diabetic...

Renal blood flow, GFR, albumin clearance, and urinary excretion of proteins were assessed in intact control and streptozotocin-diabetic rats (group 1), unilaterally nephrectomized control and diabetic rats (group 2), and nephrectomized control and diabetic rats (divided into high (a) and low (b) glycemia subgroups) fed a 50% protein diet (group 3). After 8 months of diabetes, blood flow did not differ from control rats within each experimental group, although it was increased significantly in both controls and diabetics of groups 2 and 3 versus group 1. GFR in control rats was increased approximately 2x by nephrectomy and approximately 3x by nephrectomy plus the high protein diet. Diabetes increased GFR approximately 50% above control values in group 1; GFR values in diabetic rats of groups 2 and 3a were virtually identical and similar to those of group 2 controls; GFR in group 3b diabetics was increased approximately 1.4x versus group 2 diabetics. 125I-BSA clearance was increased 3.4x in groups 2 and 3 control rats versus group 1 controls. Both nephrectomy and consumption of the high protein diet caused marked increases in 125I-BSA clearance and urinary excretion of albumin in diabetic rats. Urinary excretion of IgG was increased by diabetes in group 1 and remained essentially at this level in groups 2 and 3 diabetic rats.(ABSTRACT TRUNCATED AT 250 WORDS)