To elucidate the mode of action of adrenergic agents on gastric A cells, the effects of infusion of adrenergic agonists and antagonists on the secretion of gastrointestinal immunoreactive glucagon (gastrointestinal IRG) from gastric A cells were investigated in 45 conscious, depancreatized dogs untreated with insulin.
Large amounts (0.6 μg/kg/min) of epinephrine, norepinephrine, and isoproterenol stimulated the release of gastrointestinal (RG, and catecholamine-induced gastrointestinal IRG release was completely abolished by simultaneous infusion of the specific beta receptor-blocking compound, propranolol, but not by alpha receptor blockade with phentolamine.
These findings suggest that, when adrenergic agonists are infused in large amounts, they may act through a beta receptor to increase the release of gastrointestinal IRG.
