Effect of the degree of hyperglycaemia on the catalytic activities of glycosidases in kidney and urine of diabetic rats.

The catalytic activities of N-acetyl-beta-D-glucosaminidase, beta-galactosidase and alpha-glucosidase in kidney and urine of diabetic rats were investigated in relation to the duration of diabetes, to the degree of constant hyperglycaemia and to the therapeutic control in the early stage of disease. The results suggest that the degree of constant hyperglycaemia and the duration of untreated diabetes are significant determining factors for the course of morphological changes. These changes are manifested as a decrease of the glycosidases in kidney (0.5 to 0.6 time the age-matched controls) and as moderate to severe enzymurias. Daily variation of blood glucose with inadequate insulin Lente therapy caused decreased N-acetyl-beta-D-glucosaminidase and beta-galactosidase activities in kidney as well as enzymuria. Since such changes can be correlated with histologically visible changes in the kidney, the measurement of these enzymes in urine is a simple way of monitoring the development of kidney damage in poorly controlled diabetes. When constant normoglycaemia was maintained for three weeks with insulin Ultralente in diabetic rats with a confirmed decrease of kidney glycosidases, the persisting morphological alteration of the organ was reflected by a urinary output of N-acetyl-beta-D-glucosaminidase.