Increased serum and urinary N-acetyl-beta-D-glucosaminidase activity in human hypertension: early indicator of renal dysfunction.

The pathophysiologic significance of increased serum and urinary N-acetyl-beta-D-glucosaminidase (NAG) activity in hypertension was investigated. The subjects were 32 male patients, aged 40-65 years, with mild or borderline, uncomplicated hypertension and 26 age-matched, male normotensive volunteers. Compared to values in control subjects, NAG activity in the serum, spot and 24-hour urine samples of hypertensive subjects was increased (p less than 0.01). Serum NAG activity in hypertensive subjects was inversely correlated with glomerular filtration rate (r = -0.49, p less than 0.01, N = 31) and renal plasma flow (r = -0.56, p less than 0.02, N = 19) and positively correlated with mean arterial blood pressure (r = 0.40, p less than 0.05). The elevation of serum NAG activity in hypertension is a biochemical marker of the reduction in glomerular filtration rate and renal plasma flow.