Diabetic glomerulopathy following unilateral nephrectomy in the dog.

To elucidate the important features of early renal disease in the diabetic dog, renal capillary permselectivity and fractional mesangial expansion with and without unilateral nephrectomy (NX) were examined. Pancreatectomized mongrel dogs (N = 9) received 10-20 U Regular and NPH insulin daily. Weekly blood glucose monitoring, 300 +/- 75 mg/dl (means +/- SD). Three dogs without NX had serial open needle biopsies 6-23 months post-pancreatectomy, revealing significant glomerular basement membrane widening and mesangial expansion. Without NX, inulin clearance increased from 2.55 +/- 0.89 (pre-diabetes) to 4.30 +/- 0.70 ml/min/kg body weight (N = 4, means +/- SD, p less than 0.05), whereas albuminuria, measured by radioimmunoassay, remained unchanged 2.57 +/- 1.03 (pre-diabetes) to 2.83 +/- 1.63 micrograms/min/kg body weight up to 23 months post-pancreatectomy. To determine whether altered renal capillary permselectivity occurred despite normal albuminuria, glomerular charge and size selectivity was analysed with serial fractional anionic dextran (20-44 A Stokes Einstein Radius) clearances. Furthermore, peritubular capillary permselectivity was probed with anionic and neutral 3H-dextran (26 A) using the multiple indicator dilution method. Fractional anionic dextran clearances remained unchanged up to 23 months, as did peritubular capillary permselectivity. Five diabetic dogs were compared to non-diabetic dogs with (N = 4) and without (N = 10) NX. To identify whether angiotensin II converting enzyme inhibition modified glomerular function or morphology, 3 diabetic + NX dogs received Captopril (5 mg/kg/day). At one year, diabetes + NX had an additive effect on renal hypertrophy, although fractional mesangial expansion was not enhanced by NX. Albuminuria was unaffected by NX or Captopril.(ABSTRACT TRUNCATED AT 250 WORDS)