| Abstract: | This study investigated effects of glucagon-likepeptide-1(7-36)amide (GLP-1) on gastric emptying, smallintestinal transit, and contractility of smooth musclestrips in rats. GLP-1 at doses of 10 and 20 pmol/kg/min administered intravenouslydose-dependently retarded transit of the small intestine(P < 0.001), while only the higher dose of 20pmol/kg/min retarded gastric emptying (P < 0.01).GLP-1 at concentrations up to 10-4 M didnot affect the basal tone or contractility of thegastrointestinal muscle strips that were stimulated withelectric field stimulation or acetylcholine. Our resultsdemonstrate that small intestinal transit seems moresensitive than gastric emptying to inhibition by GLP-1at physiologic levels in plasma. Furthermore, thisinhibition appears to be mediated through centralmechanisms rather than through peripheral actions. Thus,GLP-1 is suggested to inhibit gastric emptying and smallintestinal transit through an indirect effect viacentral or enteric nervous mechanisms. |
