Endothelial cell adenylate cyclase: activation by catecholamines and prostaglandin I2
Muscle, Smooth, Vascular
Following incubation of intact vascular endothelial cells with 1 mM 3-isobutyl-1-methylxanthine, and isoproterenol or PGI2, cyclic AMP levels increased 4- and 3-fold, respectively. Isoproterenol-stimulated adenylate cyclase activity of cell lysates was selectively inhibited by the β-adrenergic blocking agent propranolol. Catecholamines stimulated adenylate cyclase with the potency series: isoproterenol > epinephrine > norepinephrine. Prostaglandin did not stimulate adenylate cyclase activity in cell lysates, even in the presence of guanine nucleotides or following preincubation of the intact cells with prostaglandins prior to freeze-thaw lysis.