Abolition of dopaminergic insulin secretion by beta-adrenergic antagonism.
To determine whether the insulinotropic effects of dopamine were mediated through the adrenergic system, dogs were infused with dopamine before or after various combinations of adrenergic and cholinergic blockade. Plasma glucose levels did not change significantly throughout the individual experiments, although cardiovascular effects from both blockade and dopamine infusion were demonstrated. The pronounced in vivo insulinotropic effects of dopamine were abolished by beta-adrenergic blockade with propranolol and all subsequent combinations of propranolol, phentolamine, and atropine. These results contrast with the in vitro suppression of insulin by dopamine, which is abolished by alpha-adrenergic blockade by phentolamine. Therefore, it may be concluded that the prevention of dopamine effects on insulin secretion by adrenergic antagonism is evidence that dopamine exerts its effects on the B cell directly or indirectly through the adrenergic system.
D000319:Adrenergic beta-Antagonists / Q000378:metabolism*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001786:Blood Glucose / Q000378:metabolism; D004285:Dogs; D004298:Dopamine / Q000494:pharmacology*; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D008297:Male; D010646:Phentolamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D013997:Time Factors
D000319:Adrenergic beta-Antagonists; D001786:Blood Glucose; D007328:Insulin; D001285:Atropine; D011433:Propranolol; D004298:Dopamine; D010646:Phentolamine