[Monitoring kidney function in patients with essential hypertension treated with enalapril].

Hypertension may to be both, cause and the results of the renal dysfunction. The N-acetyl-glucosaminidase (NAG) is a lysosomal enzyme of renal proximal tubular cells. An elevation of the enzyme activity in urine was observed in kidney diseases and also in hypertension. The aim of our study was the evaluation of the influence of the 6-months-lasting enalapril therapy on function of renal tubules and glomeruli in patients with essential hypertension. This study included 30 patients with essential hypertension (I-II grade according to WHO criteria), divided into two groups according to the initial NAG activity in urine: I-with normal NAG activity, II-with elevated NAG activity. Enalapril administered in doses 2.5-10 mg per day. The urine NAG activity, the urine and serum creatinine concentrations, the urea serum concentration and the creatinine clearance were determined after 2, 4, 8 weeks, 3 and 6 months of enalapril therapy. Simultaneously, the blood pressure and the heart rate were measured and the resting ECG was registered. In the course of the 6-months enalapril therapy of hypertension, NAG activity in urine in the group II was declined to normal values, the creatinine concentration in the urine increased in groups I and II, and the blood pressure was significantly reduced. The results of our study imply that the monitoring of the NAG activity in urine during the enalapril therapy of hypertension, may to be a indicator of protective action of the drug on the kidney and its antihypertensive efficacy.