[Effect of beta-adrenergic receptors blockade on auricular natriuretic factor, aldosterone and renine blood activity during physical exercise].

Physical exercise stimulates the renin-angiotensin-aldosterone system. However several factors affect the control of mineralocorticoid secretion. In this study, eight healthy volunteers performed maximal exercise on cycle ergometer after being pretreated for 3 days with placebo (P) or with a non selective beta-blocker (B) (pindolol 15 mg/day). Plasma reinin activity (PRA), aldosterone (ALD), atrial natriuretic factor (ANF), and kalemia (K+) were measured at rest (R) and during exercise until exhaustion (E). (table; see text) These results confirm the role of beta-adrenoceptor activation in the increased PRA during exercise. It appears an exercise-induced increase in plasma ANF which was more elevated in subjects treated with pindolol, but which had no inhibitory effect on ALD secretion in theses conditions. K+ rose during exercise and this hyperkalemia tended to be higher with a beta-blocker. It is suggested that K+ elevation counterbalance both PRA decrease and ANF increase to be responsible for the absence of change in plasma ALD during beta-blockade.