Excretion of urinary
N-acetyl-beta-D-glucosaminidase has been found to be elevated in diabetic humans and rats. This urinary
glycosidase may reflect
blood sugar control over time, since it has been significantly and positively correlated with
hemoglobin A1 in children with
insulin-dependent diabetes. Other studies have suggested that urinary NAG may predict
diabetic nephropathy. In order to more carefully define the relationship between urinary NAG excretion and blood and urine
sugars,
hemoglobin A1, and microalbuminuria, 48 rats were made diabetic by the use of
streptozotocin. All rats were uninephrectomized at 3 weeks. Of these, 23 were treated with daily
insulin injections, 25 were untreated, and both groups were compared to 13 control, nondiabetic rats. Urine volume,
glucose,
albumin, and
blood sugar were all significantly (P less than 0.05) elevated in the untreated rats compared to the treated and control groups. Urinary NAG:UCr was significantly (P less than 0.01) elevated in the untreated group with lower but still elevated levels (P less than 0.05) in the treated rats. To further define the time course of the increase in UNAG:UCr 12 rats were followed serially at 12-hr intervals for 92 hr after
streptozotocin. Urinary NAG increased significantly (P less than 0.05) at 12 hr after
streptozotocin injection and reached a plateau at 36 hr while
hemoglobin A1 did not rise until 2 weeks after onset of
hyperglycemia. Urinary NAG increases more rapidly than
hemoglobin A1 after onset of
hyperglycemia and
glycosuria.(ABSTRACT TRUNCATED AT 250 WORDS)