The effect of β1-blocker bisoprolol on atrial natriuretic peptide plasma levels in hypertensive patients

The aim of this study was to evaluate the effects of the high selective β1-blocker bisoprolol on atrial natriuretic peptide (ANP) plasma levels in patients with a moderate essential hypertension. The study was divided into two parts: a long-term and a short-term one. In part 1, the long-term effects of the drug, given orally at a daily dose of 10 mg, on plasma ANP concentrations were studied in correlation with the blood pressure and the echocardiographic dimensions of the left heart cavities in the lying position. Plasma ANP levels were raised by 20% despite the drop in blood pressure and the very small, but statistically significant, decrease in left atrial and ventricular diameters. In part 2, the acute effects of a single oral dose of 20 mg bisoprolol in relation to postural changes were studied. Plasma ANP levels in the sitting position were lower than in when lying down, but in both positions they were slightly higher after betablockers. The above findings, taken together with the literature data, favor the theory that the antihypertensive action of beta adrenergic blockers is partially due to the increased secretion of ANP.