Effects of selective and nonselective beta adrenergic agents on renin secretion in isolated perfused rat kidney

The effects of selective and nonselective beta adrenergic drugs on the renin secretion rate (RSR) in isolated perfused rat kidneys were studied. Both isoproterenol (Ipr) (nonselective agonist) and salbutamol (Salb) (beta-2 selective agonist) stimulated RSR in a dose-dependent manner. The lowest doses able to induce a significant RSR increase were 5 nM for Ipr and 50 nM for Salb. A 5-fold increase in RSR was induced by 500 nM Ipr and a 3.2-fold increase by 5 microM Salb. Renin stimulation by both agonists was suppressed by propranolol (nonselective) and by acebutolol and its derivative M&B 16,942 (beta-1 selective antagonists). Thus, renin release was stimulated or inhibited effectively by all the drugs tested, regardless of the beta selectivity of agonists and antagonists. There were no consistent relationships observed between changes in renal hemodynamics and in RSR, suggesting that the used drugs affected renin release from in vitro-perfused rat kidney through their direct effects on juxtaglomerular cells. These results indicate that renal beta adrenoreceptors involved in renin release do not fall into two distinct beta subtypes.