[Relation between the characteristic activity of the beta-adrenergic agonist isoproterenol and the percolation properties of cell membrane].

: Variations in the intrinsic activity of 1-isoproterenol and in the percentage of high affinity beta-receptor complexes have been studied under a changes in the macrostructure of reticulocyte plasma membranes. The fluid lipid fraction have been reduced in the membranes for this by phospholipase A2/BSA treatment. It was accompanied by a progressive decrease in the fraction of beta-receptors that are able to form the high affinity complexes with 1-isoproterenol (receptor--regulatory N-protein complexes). Evaluated with the ability to activate the adenylate cyclase, the intrinsic activity of 1-isoproterenol was decreased from 1 to 0 under with conditions. This variations proved to correlate strongly with each other. Thus, changes in the membrane macrostructure may directly determine an efficiency of hormone actions.