Significance of the measurement of urinary alanine aminopeptidase and N-acetyl-beta-D-glucosaminidase activity in evaluating patients with essential hypertension.

To examine the relationship between the urinary levels of alanine aminopeptidase (AAP) or N-acetyl-beta-D-glucosaminidase (NAG) and the advance of essential hypertension, we measured the urinary levels of these enzymes in 20 normotensive controls, 8 subjects with borderline hypertension and 40 subjects with WHO stage I and stage II essential hypertension. The urinary level of NAG in stage II hypertensives was higher than that in the normotensives, and borderline or stage I hypertensives (p less than 0.01). Systolic blood pressure and the urinary level of NAG was positively correlated in hypertensives (rs = 0.43, p less than 0.01). The urinary level of NAG was correlated inversely with renal blood flow (rs = -0.61, p less than 0.01). The urinary level of AAP in stage II hypertensives was also higher than that in the normotensives (p less than 0.01) or stage I hypertension (p less than 0.01), but the urinary AAP level was not significantly correlated with systolic blood pressure or renal blood flow in hypertension.