The contribution of the distal gastrointestinal tract to glucagon-like immunoreactivity secretion in the rat.

Radioimmunoassay of acid ethanol extracts of the rat intestinal tract showed the presence of glucagon-like immunoreactivity (GLI) from the duodenum to the colon with maximal concentrations in the ileum and colon. Twenty percent glucose instilled in the duodenum at a dose of 2g/kg body weight stimulated a twofold increase in peripheral plasma GLI concentration. When the instilled glucose load was restricted to only the duodenum and jejunum, or to only the ileum and colon, the increase in peripheral plasma GLI was approximately half that seen when the entire gut was exposed to the glucose. It is concluded that the distal gut as well as the proximal gut releases GLI in the rat.