Decreased glomerular proteinase activity in the streptozotocin diabetic rat

Decreased glomerular proteinase activity may contribute to matrix accumulat ion in diabetes. Male Sprague-Dawley rats were rendered diabetic by injecti on of streptozotocin (STZ) 65 mg/kg i.v.; age-matched, sham-injected rats s erved as controls. Glomeruli from diabetic rats 1 month after STZ injection demonstrated significant decreases in collagenase and cathepsin B activiti es compared to control glomeruli, Treatment with insulin resulted in a slig ht (but not significant) increase in collagenase activity and normalized ca thepsin B activity. We conclude that decreased glomerular collagenase and c athepsin B activities are present in STZ diabetes. These alterations may co ntribute to mesangial matrix accumulation.