Catecholamine-sensitive adenylate cyclase of human fat cell ghosts: a comparative study using different beta-adrenergic agents.
Some of the effects of beta-adrenergic agonists and antagonists on the adenylate cyclase system of human fat cell ghosts were studied. Isoproterenol, by causing about a fourfold increase of enzyme activity, was more potent than epinephrine and norepinephrine (about 2.5--3.0-fold stimulation). The beta2-adrenergic agonists salbutamol, terbutalin, and fenoterol were considerably less effective than the naturally occurring catecholamines. The stimulatory actions of isoproterenol and beta2-adrenergic agonists were competitively inhibited by the beta-blocking agent propranolol. Isoproterenol stimulation was also inhibited by the selective beta1-adrenergic antagonist practolol. This compound, however, was less potent than propranolol. The results are suggestive for an adenylate cyclase system in human fat cell ghosts coupled to beta1-adrenergic receptor sites. These receptors differ from the cardiac beta receptors with respect to practolol affinity.
D000262:Adenylyl Cyclases / Q000378:metabolism*; D000273:Adipose Tissue / Q000166:cytology / Q000201:enzymology*; D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000420:Albuterol / Q000494:pharmacology; D004790:Enzyme Induction; D004837:Epinephrine / Q000494:pharmacology; D005280:Fenoterol / Q000494:pharmacology; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D011217:Practolol / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011943:Receptors, Adrenergic, beta / Q000502:physiology; D013726:Terbutaline / Q000494:pharmacology
D000318:Adrenergic beta-Agonists; D011943:Receptors, Adrenergic, beta; D005280:Fenoterol; D011433:Propranolol; D000262:Adenylyl Cyclases; D007545:Isoproterenol; D013726:Terbutaline; D000420:Albuterol; D011217:Practolol; D009638:Norepinephrine; D004837:Epinephrine