Etude par manométrie endoscopique de l'action du Glucagon et du Glucagon 1–21 sur le sphincter d'Oddi

Effect of Glucagon-(1–21)-Peptide on Gastroduodenal Motility during Upper Gastrointestinal Examination

The inhibitory effect of glucagon-(1–21)-peptide on the motility of the stomach and duodenum during radiologic double contrast studies was examined. In a randomized trial of equimolar doses of glucagon and glucagon-(1–21)-peptide on 70 patients, glucagon-(1–21)-peptide showed to have a significantly weaker effect than glucagon. Glucagon caused significant increases in plasma-glucose and plasma-insulin, while glucagon-(1–21)-peptide had no such effects. In a subsequent randomized study on 75 patients glucagon-(1–21)-peptide in various doses was tested against placebo. The effect was insignificant from that of placebo at practically all dose levels. No side effects were registered. It is concluded, that glucagon-(1–21)-peptide probably has a certain relaxing effect on the smooth muscle of the stomach and duodenum, but that this effect is too small for practical clinical use.

Effect of glucagon-(1-21)-peptide on secretin-stimulated pancreatic exocrine secretion in anesthetized dogs

The effects of glucagon-(1-21)-peptide on pancreatic exocrine secretion and plasma glucose levels were studied and compared with those of native glucagon in anesthetized dogs. Intravenous bolus administration of 1 nmol or 10 nmol/kg of glucagon-(1-21)-peptide evoked a significant inhibition of secretin-stimulated pancreatic juice secretion and protein output in a dose-dependent manner, as equimolar doses of glucagon did. Native glucagon induced an immediate and transient increase in pancreatic juice volume, which was followed by a significant inhibition. However, glucagon-(1-21)-peptide showed only the inhibitory action. Glucagon-(1-21)-peptide had no effect on plasma glucose levels even when a dose of 10 nmol/kg was given. The results suggest that the N-terminal amino-acid residues of glucagon play an important role in the inhibition of pancreatic exocrine secretion.

The effects of glucagon and glucagon-(1-21)-peptide on antroduodenal motility in healthy volunteers

Since it has been argued that the spasmolytic effect of glucagon is related to the first 21 N-terminal amino acid residues, and not to the complete molecule, we have compared the effects of glucagon-(1-21)-peptide (G-(1-21) and glucagon on human antroduodenal motility. Glucagon and G-(1-21) were given as bolus injections to 30 healthy volunteers equally allocated into five groups. Each subject received two doses; one was placebo, 0.25, 0.5, 1.0 or 2.0 mg of glucagon, the other was an equimolar doses of G-(1-21) (placebo, 0.175, 0.35, 0.70 or 1.4 mg of G-1-21). The first injection was given during phase II of a migrating motility complex (MMC), and the next during the following phase II. Contractile activity was recorded using an oral tube with one sidehole positioned in the antrum and two in the duodenum. We confirmed that glucagon decreases the number of contractions in the antrum and duodenum and that normal phase II activity was restored within 20-40 minutes proportionally to the amount of the drug given. G-(1-21) did not change antroduodenal motility nor did it affect the phase II pattern in any of the groups. Neither were any side effects encountered. G-(1-21) does not seem to be an alternative to glucagon and other spasmolytic drugs for obtaining relaxation of the antroduodenal area.