BOTH BETA-1-ADRENOCEPTOR AND BETA-2-ADRENOCEPTOR ARE INVOLVED IN MEDIATING PHOSPHATIDYLCHOLINE SECRETION IN RAT TYPE-II PNEUMOCYTE CULTURES

A primary culture of rat type II pneumocytes was used for the pharmacological and functional characterization of beta-adrenoceptor subtypes. The beta-adrenoceptor agonists, isoprenaline, dobutamine and procaterol concentration dependently increased the secretion of phosphatidylcholine. These effects were attenuated by propranolol. The effect of dobutamine was attenuated by atenolol, and that of procaterol by ICI 118,551. Isoprenaline-induced secretion was attenuated by the combination of the two blockers but not by each one alone. In conclusion, both beta-1- and beta-2-adrenoceptor subtypes mediate phosphatidylcholine secretion in rat type II pneumocytes.