Abstract
Renin infusion produced initial increase in blood pressure and peripheral resistance. As infusion continued, blood pressure returned to base-line levels, but peripheral resistance remained slightly elevated. Noradrenaline infusion in the dog did not produce sustained hypertension, but the peripheral resistance remained elevated. Repeated renin injections finally produced no change of blood pressure or peripheral resistance. At this time the animal was nonresponsive to angiotensin. Return of blood pressure to base-line levels despite continued infusion of renin was felt to represent both a ‘cardiovascular failure of response’ and a more specific blockade of angiotensin response.