Abstracts
Résumé
L’ingestion de nourriture déclenche une réponse hormonale complexe, dont le but est notamment de minimiser les oscillations de la glycémie grâce à une stimulation appropriée du captage de glucose par le foie et les tissus musculaire et adipeux. L’activité insulinosécrétoire des cellules β du pancréas joue un rôle majeur dans cette réponse. Bien que l’augmentation du glucose sanguin soit le stimulus principal de l’insulinosécrétion, des hormones intestinales, libérées par des cellules endocrines de l’épithélium intestinal lors du passage de nutriments, jouent un rôle important de potentialisation de l’effet du glucose sur les cellules β pancréatiques. Ces hormones, appelées gluco-incrétines, sont principalement le GLP-1 (glucagon like peptide-1) et le GIP (glucose-dependent insulinotropic polypeptide). Elles agissent au niveau des cellules β pancréatiques en se liant à des récepteurs heptahélicaux couplés à l’activation de l’adénylate-cyclase. Outre leur capacité de potentialiser la sécrétion d’insuline induite par le glucose, ces hormones stimulent également la production d’insuline par des effets transcriptionnels et post-transcriptionnels, et ont également un effet positif sur le contrôle de la masse cellulaire β. L’activité insulinotrope, dépendante du glucose, du GLP-1 étant préservée au cours du diabète de type 2, ce peptide est considéré comme un médicament potentiel pour le traitement de cette maladie.
Summary
Nutrient ingestion triggers a complex hormonal response aimed at stimulating glucose utilization in liver, muscle and adipose tissue to minimize the raise in blood glucose levels. Insulin secretion by pancreatic β cells plays a major role in this response. Although the β cell secretory response is mainly controlled by blood glucose levels, gut hormones secreted in response to food intake have an important role in potentiating glucose-stimulated insulin secretion. These gluco-incretin hormones are GLP-1 (glucagon-like peptide-1) and GIP (gluco-dependent insulinotropic polypeptide). Their action on pancreatic β cells depends on binding to specific G-coupled receptors linked to activation of the adenylyl cyclase pathway. In addition to their effect on insulin secretion both hormones also stimulate insulin production at the transcriptional and translational level and positively regulate β cell mass. Because the glucose-dependent insulinotropic action of GLP-1 is preserved in type 2 diabetic patients, this peptide is now developed as a novel therapeutic drug for this disease.
Appendices
Références
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