title: Inhibition by isoproterenol of the passive potassium efflux from pigeon erythrocytes.
abstract: Pigeon erythrocytes were carefully washed in an isotonic neutral buffer, devoid of potassium, and the rate of passive unidirectional efflux of potassium from the cells into a K+-free medium was measured after 20 min, at 40 degrees C. Isoproterenol inhibits K+-efflux by 35-45%, at a cell concentration of 1%; the isoproterenol effect is mediated by beta-adrenergic receptors. Cyclic AMP mimics the effect of isoproterenol, but at 4-5 orders of magnitude higher concentrations. Cyclic AMP increases 20-fold the phosphorylation of purified cell membranes by [gamma 32P]ATP.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D010856:Columbidae; D000242:Cyclic AMP / Q000494:pharmacology; D004910:Erythrocyte Membrane / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism*; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology*; D010766:Phosphorylation; D011188:Potassium / Q000097:blood / Q000378:metabolism*; D011433:Propranolol / Q000494:pharmacology
chemical_list: D000255:Adenosine Triphosphate; D011433:Propranolol; D000242:Cyclic AMP; D007545:Isoproterenol; D011188:Potassium