Most potent vasopresser is:

Ganong 22 –456 Angiotensin I appears to function solely as the precursor of angiotensin II does not have any other established action. Angiotensin II- previously called hypertension or angiotonin- produces arteriolar constriction and a rise in systolic and diastolic blood pressure. It is one of the most potent vasoconstrictors known, being four to eight times as active as norepinephrine.