title: Cyclic AMP phosphodiesterase in cloned astrocytoma cells: norepinephrine induces a specific enzyme form.
abstract: The soluble supernatant fraction of homogenates of cloned rat astrocytoma cells (linle C-2A) was subjected to polyacrylamide gel electrophoresis. Two peaks of adenosine 3',5'-monophosphate phosphodiesterase activity were found, corresponding to peaks I and IV of a similarly prepared homogenate of rat brain. Incubating cells with norepinephrine (0.3 mullimolar) caused about a threefold increase in the activity of peak IV but no change in peak I. This increase was completely inhibited by prior inclubation with propranolol (0.1 millimnolar), a beta-adrenergic blocking agent, or with cyclohexamnine (40 micromolar). a protein synthesis inhibitor. Induction of a specific phosphodiesterase form by norepinephrine sitggests another feedback control mechanism whereby an organism can prevent the effects of excessive sympathetic activity.
mesh_terms: D000818:Animals; D001254:Astrocytoma / Q000201:enzymology*; D002460:Cell Line; D002999:Clone Cells; D000242:Cyclic AMP; D003513:Cycloheximide / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004790:Enzyme Induction; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D010727:Phosphoric Diester Hydrolases / Q000096:biosynthesis*; D011433:Propranolol / Q000494:pharmacology; D051381:Rats
chemical_list: D003513:Cycloheximide; D011433:Propranolol; D000242:Cyclic AMP; D010727:Phosphoric Diester Hydrolases; D009638:Norepinephrine