title: Hepatic adrenoceptors involved in the glycogenolytic response to exogenous (-)-norepinephrine in the dog liver in vivo.
abstract: Effects of various sympathomimetic amines on the hepatic glucose mobilization were studied in anesthetized dogs. Phenylephrine (30, 100, 300 micrograms), isoproterenol (0.1, 1, 10 micrograms) and (-)-norepinephrine (0.5, 5, 50 micrograms) were injected into the common hepatic artery in three separate groups of dogs. Dose-dependent increases in hepatic venous glucose concentration were observed following the injections of these drugs. Aortic glucose concentration also increased significantly, but to a lesser extent as compared with that in hepatic venous blood. Peak responses were obtained 3 to 5 min after the drug administrations. The increases in hepatic venous glucose concentration induced by the injections of (-)-norepinephrine were significantly diminished to a similar extent in dogs treated with either phentolamine (2 mg/kg, i.v.) or (-)-propranolol (0.2 mg/kg, i.v.). The results indicate that in the dog liver in vivo, both hepatic alpha- and beta-adrenoceptors can be involved in the hepatic glycogenolysis. The glycogenolytic response to exogenously administered (-)-norepinephrine is mediated via alpha- as well as beta-adrenoceptors in the liver of anesthetized dogs.
mesh_terms: D000818:Animals; D001011:Aorta; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure; D004285:Dogs; D006003:Glycogen / Q000378:metabolism*; D006499:Hepatic Artery / Q000187:drug effects / Q000502:physiology; D006503:Hepatic Veins; D007545:Isoproterenol / Q000494:pharmacology; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology*; D010646:Phentolamine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D012039:Regional Blood Flow
chemical_list: D001786:Blood Glucose; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D010656:Phenylephrine; D006003:Glycogen; D011433:Propranolol; D007545:Isoproterenol; D009638:Norepinephrine; D010646:Phentolamine