Angiotensin II. Vascular reactivity and humoral effects.

The vasopressor response to angiotensin II was found useful in the differential diagnosis of arterial hypertension and for a better understanding of its pathogenesis. Sodium supply was proved to influence significantly the pressor response to angiotensin II and not that to noradrenaline thus implying the presence of arterial receptors which bind angiotensin specifically. Angiotensin caused an increase of the urinary excretion of electrolytes in hypertensive patients and a decreased electrolyte excretion in normotensives. In most hypertensive patients angiotensin was found to decrease the plasma angiotensinogen and to activate the bradykinin-bradykininogen and fibrinolytic systems. In the presence of urinary infection angiotensin increased the platelet adhesiveness and the thrombelastographic changes proved that in this condition angiotensin increases the tendency to thrombosis.