Depletion of sialic acid without changes in sialidase activity in glomeruli of uninephrectomized diabetic rats.

The role of sialidase in the depletion of glomerular sialic acid induced by diabetes has been investigated in uninephrectomized rats. Four months after streptozotocin administration, diabetic rats showed an enhanced urinary excretion of albumin and transferrin, which was associated with a decrease of sialic acid concentration in isolated glomeruli. Despite the sialic acid depletion, the glomerular sialidase activity was unchanged. These results indicate that the decreased glomerular sialic acid concentration observed in diabetic nephropathy might be caused by a disturbance of the sialylation of glomerular structures.