title: Effect of hormonal and neuronal agents on adenylate cyclase from smooth muscle of the gastric antrum.
abstract: Smooth muscle adenylate cyclase of a membrane preparation of canine gastric antrum has been characterized, and the effect of hormonal and neuronal agents examined. The enzyme is active in the presence of Mg2+ or Mn2+, but is inhibited by Ca2+. The Km is 0.5 mM ATP, similar to the Km of skeletal muscle adenylate cyclase. The enzyme is activated by isoproterenol but not norepinephrine, consistent with a beta 2-catecholamine receptor-adenylate cyclase interaction. Secretin activates the enzyme in concentrations as low as 1 . 10(-11) M, while glucagon was effective only at 1 . 10(-6) M. Prostaglandin E1 and E2 have a biphasic effect with activation of adenylate cyclase at 1 . 10(-5) M and a small but significant inhibition of enzyme activity at 1 . 10(-11) M.
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D002766:Cholecystokinin / Q000494:pharmacology; D004285:Dogs; D005755:Gastrins / Q000494:pharmacology; D005934:Glucagon / Q000494:pharmacology; D007545:Isoproterenol / Q000494:pharmacology; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D009130:Muscle, Smooth / Q000201:enzymology*; D009708:Nucleotidases / Q000378:metabolism; D011458:Prostaglandins E / Q000494:pharmacology; D011706:Pyloric Antrum / Q000201:enzymology*; D012633:Secretin / Q000494:pharmacology
chemical_list: D005755:Gastrins; D011458:Prostaglandins E; D012633:Secretin; D008345:Manganese; D005934:Glucagon; D002766:Cholecystokinin; D009708:Nucleotidases; D000262:Adenylyl Cyclases; D008274:Magnesium; D007545:Isoproterenol