title: Beta-adrenergic receptors and myogenesis.
abstract: The rat myogenic cell line, L8, contains a beta-adrenergic catecholamine-sensitive adenylate cyclase. Prior to cell fusion, and continuing thereafter, beta-adrenergic sites, as determined by the stereospecific binding of (125I)-hydroxybenqylpindolol, I1(125I)IHYP] increases from 470 to 2000 sites/cell. There is also an increase in adenylate cyclase (2-5 fold) and endogenous cAMP (5-30 fold) following stimulation by catecholamine. The dissociation constant (KD) of (125I)IHYP for unfused and fused cell-homogenates, as determined by estimation with Scatchard analysis, by direct determination at receptor concentrations well below the KD, or by association (4.6 X 10(8) M-1 min-1); and dissociation (0.028 min-1) kinetics; ranged from about 40 to 70 pM. The acquisition of beta-receptors prior to fusion in L8 cells may implicate this system in the regulation of myogenesis.
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D002454:Cell Differentiation; D002459:Cell Fusion; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism; D007545:Isoproterenol / Q000494:pharmacology; D007700:Kinetics; D009132:Muscles / Q000502:physiology*; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism*; D013806:Theophylline / Q000494:pharmacology
chemical_list: D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; D013806:Theophylline; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D007545:Isoproterenol