Inhibitory effects of beta-adrenergic agonists on gastric acid secretion in dogs.
We evaluated the effect of two beta-adrenergic agonists, isoproterenol (nonselective agonist) and terbutaline (selective beta 2-agonist), on gastric acid secretion stimulated by intravenous pentagastrin, bethanechol, or histamine in dogs with gastric fistulas. Intravenous infusion of isoproterenol or terbutaline inhibited pentagastrin-stimulated acid secretion to a significantly greater extent than they inhibited bethanechol- or histamine-stimulated acid secretion. For example, isoproterenol (12 micrograms X kg-1 X h-1) reduced mean pentagastrin-, bethanechol-, and histamine-stimulated acid output by 86, 63, and 14%, respectively. Percent inhibition of acid secretion with terbutaline (30 micrograms X kg-1 X h-1) averaged 60, 17, and 24% for pentagastrin, bethanechol, and histamine, respectively. Terbutaline also inhibited pentagastrin-stimulated acid secretion from vagally denervated fundic pouches in a dose-related manner. Plasma somatostatin-like immunoreactivity was significantly higher during infusion of terbutaline plus pentagastrin than during infusion of pentagastrin alone. However, an intravenous infusion of 0.3 microgram X kg-1 X h-1 somatostatin-14 had no effect on pentagastrin-stimulated acid secretion from the gastric fistula, even though this infusion increased plasma somatostatin-like immunoreactivity to the same extent as terbutaline plus pentagastrin infusion. Thus the amount of somatostatin released during terbutaline infusion was not sufficient to explain the inhibition of pentagastrin-stimulated acid secretion observed.
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D018723:Bethanechol; D001626:Bethanechol Compounds / Q000494:pharmacology; D004285:Dogs; D005744:Gastric Acid / Q000378:metabolism*; D005755:Gastrins / Q000097:blood; D006632:Histamine / Q000494:pharmacology; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D010418:Pentagastrin / Q000494:pharmacology; D010455:Peptides / Q000097:blood; D013726:Terbutaline / Q000494:pharmacology; D014628:Vagotomy
D000318:Adrenergic beta-Agonists; D001626:Bethanechol Compounds; D005755:Gastrins; D010455:Peptides; C029993:somatostatin-like peptides; D018723:Bethanechol; D006632:Histamine; D010418:Pentagastrin; D007545:Isoproterenol; D013726:Terbutaline