Increased serum N-acetyl-beta-D-glucosaminidase activity in human hypertension.

Compared to values obtained in healthy normotensive control subjects, serum activity of the lysosomal enzyme N-acetyl-beta-D-glucosaminidase (NAG) was found to be elevated in patients with untreated or treated essential hypertension and in patients with renovascular hypertension. Increased NAG activity in hypertension could not be ascribed to tissue necrosis because the serum levels of several commonly measured cytosolic enzymes were within normal limits. The kidney is a likely but unproven source of the enzyme elevation in hypertension.