Urinary N-acetyl-B-D-glucosaminidase, microalbuminuria, and microtransferrinuria as indicators of diabetic nephropathy

ABSTRACT

Urinary levels of total protein, albumin and transferrin [as estimates of glomerular function] and urinary N-acetyl-B-D-glucosaminidase [NAG] activity [as estimate of tubular function] were determined in 10 healthy control persons [GI] and in 40 insulin-dependent diabetic patients, 10 patients with clinical proteinuria [GIII] and the other 30 patients without clinical proteinuria [GII]. Group II was further subgrouped according to the duration of diabetes into three subgroups GIIa [10 patients with duration of less than 2 years], GIIb [10 patients with duration of 2 to 10 years, and GIIc [10 patients with duration of more than 10 years]. The patients and controls were also investigated for fasting blood glucose, glycosylated hemoglobin and creatinine clearance. In diabetics with clinical proteinuria, urinary levels of total protein, albumin and NAG activity were significantly increased when compared with other groups. Also, urinary transferrin was only detected in this group. In diabetics without clinical proteinuria creatinine clearance was significantly increased in group IIa and IIb when compared with controls and in group IIb when compared with group IIc. There was a significant increase in microalbuminuria in group IIc when compared with the control, group IIa and group IIb. Also, urinary NAG activity was significantly increased in group IIc when compared with the control and group IIa. Urinary albumin and transferrin were found to be negatively correlated to the creatinine clearance in group III, while there was a positive correlation between urinary transferrin and urinary albumin and total urinary protein in the same group