In the current project we wish to identify the possible contribution of extrapancreatic effects on gastrointestinal-mediated glucose disposal (GIGD). GIGD reflects the percentage of an individual's glucose disposal following oral glucose tolerance test (OGTT) which is caused by the oral route of glucose administration. In healthy subjects GIGD amounts to ~60%. GIGD describes not only the impact of the incretin effect (insulinotropic substances released upon intestinal stimulation) but includes all factors affecting glucose disposal differently during oral vs. iv administration of glucose (including neural reflexes, activation of afferent nerves in the intestinal mucosa, differences in glucagon secretion, hepatic glucose production and first-pass hepatic uptake of glucose, differences in portal and venous blood glucose concentrations and/or at the present unknown factors. It is likely that the incretin effect (pancreatic effect) constitutes a major contributor to GIGD, but so far it has been impossible to discriminate between pancreatic and extrapancreatic mechanisms underlying GIGD