1. In the conscious normotensive and two-kidney Goldblatt hypertensive dog a transient agonist response to the intravenous infusion of saralasin (1 μg min−1 kg−1) was manifested by a small increase in blood pressure (6–12 mmHg) and 28–30% increase in renal vascular resistance.
2. These increases in blood pressure and renal vascular resistance were unaffected by administration of either phentolamine or guanethidine.
3. The agonist response in the conscious dog is most likely accounted for by a direct action of saralasin on vascular angiotensin receptors.