N-ACETYL-BETA-D-GLUCOSAMINIDASE LEVELS AND DIABETIC MICROANGIOPATHY

N-Acetyl-β-d-glucosaminidase (NAG) activity has been measured in the serum and urine of primary and secondary diabetics and in primary diabetics with microangiopathy. NAG activity has also been measured in the tears of diabetics with ocular complications and diabetics with no ocular changes. Results have shown significantly higher levels of urinary NAG in diabetics with proteinuria (p < 0.001) and proteinuria and retinopathy (p < 0.001). There was no correlation between urinary NAG activity and serum creatinine (r = 0.28) or urinary NAG and the degree of proteinuria (r = 0.24). Increased urinary NAG levels were also observed in secondary diabetes associated with haemochromatosis and acromegaly. Significantly higher serum NAG levels were found in newly diagnosed diabetics (p < 0.01) and significantly lower levels in chemical diabetics (p < 0.01). Compared to non-diabetic controls tear NAG levels were significantly higher in the diabetic controls (p < 0.01), in diabetics with retinopathy (p < 0.01), and in diabetics with cataract formation (p < 0.05). An assessment of this enzyme is made in relation to the development of diabetic microangiopathy. © 1979.