A group of patients with essential hypertension and healthy subjects from the same work place were investigated for a period of four weeks and were subjected, in addition to a basic clinical medical examination, to an ergometric examination ECHO cardiography, occlusion plethysmography, and concurrently serum levels of adrenaline (A), noradrenaline (NA), renin, cyclic adenosine monophosphate (cAMP) beta receptors before and after four weeks treatment with enalapril were assessed. The results are consistent with available data from the literature where administration of inhibitors of the angiotensin converting enzyme (ACE) caused a reduction of the peripheral vascular resistance and increased blood flow assessed by means of occlusion plethysmography. Similar results were recorded after captopril administration for a one year period, as reported by Agabiti-Rose (1). Statistically significant differences were detected between hypertonics given placebo and those given enalapril for four weeks, as regards blood flow at rest and peripheral vascular resistance at rest. There was also a significant difference when hypertonic and normotonic subjects were compared. The results are presented in tables and figures.

Keywords: Adult; Blood Pressure /drug effects/; Cyclic AMP /blood/; Enalapril /therapeutic use/; Epinephrine /blood/; Humans; Hypertension /blood/; Male; Norepinephrine /blood/; Plethysmography; Renin /blood/; Vascular Resistance /drug effects/