MEPRIN ACTIVITY IN RATS WITH EXPERIMENTAL RENAL-DISEASE

Activity of renal meprin, a membrane-bound proteinase in the proximal tubule brush border, was measured in normal rats and in two disease gr oups: chronic puromycin aminonucleoside nephropathy for 12 weeks and s treptozocin-induced diabetes for 6 months. Enzyme activity in kidney h omogenates was assayed using azocasein as substrate. The mean activity of meprin was 3.22+/-0.34 U/g kidney weight in normal rats. In diabet ic animals, enzyme activity was 8.58+/-2.11 U/g kidney weight, P<0.01. In contrast, meprin activity was decreased in rats with puromycin-ind uced glomerulopathy, 2.13+/-0.17 U/g kidney weight, P<0.01. These find ings indicate that meprin activity is elevated in experimental diabete s. Diminished activity of this luminal membrane enzyme in puromycin am inonucleoside nephropathy may contribute to renal injury in this disea se model associated with massive urinary protein excretion.