Effects of selective and non-selective beta-adrenergic agents on insulin secretion in vivo.
The effects of various beta-adrenergic agents on insulin secretion were investigated in vivo in mice. The non-selective beta-stimulator isopropylnoradrenaline and the selective beta 2-stimulator terbutaline both stimulated insulin secretion markedly, with the same efficacy and in a dose-dependent manner. The peak levels of plasma insulin after these two beta-agonists were achieved at a later time point (5-6 min) than after stimulation with glucose or carbachol (1.5-2.5 min). At very high dose levels the beta 2-stimulator isopropylaminothiazoloxypropanol slightly increased plasma insulin concentrations. The non-selective beta-blocker propranolol and the beta 2-selective blocker ICI 188,551 inhibited terbutaline-induced insulin release markedly and at comparable low dose levels, whereas the selective beta 1-blocker metoprolol exerted this effect only at a high dose level. At higher dose levels these three blockers moderately depressed the insulin response to glucose suggesting a partial dependence on intact beta-adrenoceptors for the effect of glucose. The beta 2-blocker butoxamine and the beta 1-blocker pamatolol did not influence insulin secretion. In conclusion, beta-adrenoceptor stimulation enhanced insulin secretion in vivo, but the beta-adrenoceptors regulating insulin secretion do not fit well into the conventional subdivision of beta 1 and beta 2, though they apparently are mainly of the beta 2-type.
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D002078:Butoxamine / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007545:Isoproterenol / Q000494:pharmacology; D008790:Metoprolol / Q000494:pharmacology; D051379:Mice; D011412:Propanolamines / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D013726:Terbutaline / Q000494:pharmacology; D013844:Thiazoles / Q000494:pharmacology
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D007328:Insulin; D011412:Propanolamines; D013844:Thiazoles; D002078:Butoxamine; C026777:ICI 118551; D002217:Carbachol; D011433:Propranolol; C002268:tazolol; D008790:Metoprolol; D005947:Glucose; D007545:Isoproterenol; D013726:Terbutaline