[Participation of the gastrointestinal tract in regulating the processes of insulin liberation by the pancreas].

Three elevations of the insulin concentration in the blood of the v. pancreaticoduodenalis and v. portae were found in dogs fed with food containing mainly proteins, fat or carbohydrates. The gastrointestinal tract was found to potentiate the liberation of insulin. The elevation of the latter concentration in the blood occurred before the intensive absorption of the nutrients aided to, apparently, by liberation of some gastrointestinal hormones (gastrin, cholecystokinin-pancreozymin, GIP and others) which prepare the tissues for the assimilation of nutrients. A later elevation of the insulin concentration in the blood is possibly connected with absorption of aminoacids and some other nutrients and/or liberation of GIP in the small intestine.