Effect of beta-adrenergic blockade on plasma levels of atrial natriuretic peptide during exercise in humans.

Effect of beta-adrenergic blockade on plasma levels of atrial natriuretic peptide (ANP) during treadmill exercise was studied in 9 healthy volunteers. Plasma ANP levels increased during exercise. The mean plasma ANP concentration on 12-min exercise (32.5 +/- 3.7 pg/ml, mean +/- SEM) was significantly higher than the control (16.7 +/- 1.0 pg/ml). After exercise, the levels decreased and the mean plasma ANP concentrations in the recovery period were higher in subjects in the sitting position than in subjects who kept standing. Prior administration of a long-acting propranolol, 160 mg daily for 3 consecutive days, augmented ANP release during exercise. The mean plasma ANP concentrations on 9- and 12-min exercise (34.5 +/- 3.1 and 64.9 +/- 15.0 pg/ml, respectively) were significantly higher than those in the corresponding exercise stage without propranolol. Plasma ANP levels in the recovery period also increased after the administration of propranolol and the subjects in the sitting position again had higher plasma levels than those in the standing position. These results suggest that increased central blood volume during exercise elevates atrial pressure to stimulate ANP secretion, and that greater atrial distension and pressure due to reduced ventricular contractility by beta-adrenergic blockade facilitates ANP release to a greater extent.