Diabetes, Vol 39, Issue 8 989-995, Copyright © 1990 by American Diabetes Association
Reversal of glomerular hyperfiltration and renal hypertrophy by blood glucose normalization in diabetic rats
S Stackhouse, PL Miller, SK Park and TW Meyer
Department of Medicine, Stanford University, California.
Two groups of rats with streptozocin-induced diabetes and one group of
nondiabetic control rats were studied. Group 1 diabetic rats received daily
insulin to maintain blood glucose levels at 300-400 mg/dl for 44 wk. Group
2 diabetic rats received the same insulin regimen for 37 wk and then
received an increased dose of insulin to return blood glucose levels close
to normal for 7 wk. Group 3 nondiabetic rats were age-matched controls.
Glomerular filtration rate (GFR) and kidney weight were elevated in
moderately hyperglycemic group 1 rats compared with group 3 rats.
Normalization of blood glucose returned both GFR (group 1, 1.83 +/- 0.04
ml/min; group 2, 1.36 +/- 0.05 ml/min; group 3, 1.45 +/- 0.07 ml/min) and
kidney weight (group 1, 2.55 +/- 0.06 g; group 2, 1.82 +/- 0.05 g; group 3,
1.72 +/- 0.06 g) to normal in group 2 rats. Despite a sustained increase in
GFR, group 1 rats did not exhibit any increase in glomerular volume (group
1, 2.77 +/- 0.09 x 10(6) microns3; group 2, 2.69 +/- 0.09 x 10(6) microns3;
group 3, 2.81 +/- 0.7 x 10(6) microns3). Group 1 rats did, however, exhibit
a significant increase in glomerular mesangial volume (group 1, 0.31 +/-
0.02 x 10(6) microns3; group 2, 0.28 +/- 0.02 x 10(6) microns3; group 3,
0.21 +/- 0.01 x 10(6) microns3), which was not reversed by normalization of
blood glucose in group 2. These findings show that normalization of blood
glucose can reverse established glomerular hyperfiltration and renal
hypertrophy in moderately hyperglycemic diabetic rats. They further
indicate that mesangial expansion is associated with sustained moderate
hyperglycemia in this disease model.