Contents - 1. Design of the entero-insular axis. 2. Proglucagon gene structure and regulation od expression. 3. Posttranslation processing of proglucagon of postsecretort fate of proglucan products. 4. Morphological aspects of GLP-1 expression in the intestine. 5. Release of GLP-1 into the circulation. 6. Glucagon-like peptide-1 receptor in relation to its ligand. 7. Effects of GLP-1 on islet hormone secretion: experimental studies. 8. In vivo regulation of human islet hormone secretion by glucagon-like peptide-1. 9. Signal transduction of GLP-1. 10. Islet genes regulated by GLP-1. 11. Glucagon-like peptide-1 and the glucose competence concepts of pancreatic beta-cell function. 12. Effects of GLP-1 on gastric acid and pancreatic exocrine secretion and on gastrointestinal motility. 13. Glucagon-like peptide-1 in the central nervous systems. 14. Extrapancreatic action of GLP-1. 15. Lessons from human studies with glucagon-like petide-1: potential of the gut hormone for clinical use.