The renin-angiotensin system and the antihypertensive effect of atenolol in man.

The effects on arterial pressure of saralasin and short-term (seven days) administration of the cardioselective beta-blocker atenolol were compared in 21 patients with various forms of hypertension. During saralasin administration mean arterial pressure (MAP) decreased by 8.8 +/- 2.1 per cent. Atenolol administration was associated with a MAP fall of 23.6 +/- 2.9 per cent. The change in MAP induced by atenolol was higher than that produced by saralasin (P less than 0.001) and no significant correlation (r = 0.40, P greater than 0.05) between their respective effects was found. These results suggest that the antihypertensive action of atenolol is not related to pre-treatment activity of the renin-angiotensin system as estimated by the hypotensive effect of saralasin. Other mechanisms should be sought in order to explain the effectiveness of this betablocker in hypertensive patients.