Half life of gastrointestinal glucagon-like immunoreactive materials

The composition, half life and hyperglycemic action of the porcine gastrointestinal glucagon-like immunoreactive materials were examined. Glucagon immunoreactivity (GI) measured using specific antiglucagon serum was more abundunt in the extract from the gastric fundus than in the one from the small intestine. When the extract from the gastric fundus was injected in dogs, the half life (T1/2) of total glucagon-like immunoreactivity (total GLI) measured using nonspecific antiglucagon serum was 9.5 +/- 1.1 min (mean +/- SEM), which was longer than that of crystalline pancreatic glucagon, 3.4 +/- 0.2 min, but shorter than that of the extract from the small intestine, 15.9 +/- 1.3 min. On the other hand, T1/2 for GI from the gastric fundus was 5.1 +/- 0.9 min, which was not significantly different from that of crystalline pancreatic glucagon. Blood sugar levels were significantly increased from the basal by 25 +/- 4 mg/100 ml at 10 min and 19 +/- 4 mg/100 ml at 15 min following an injection of the extract from the gastric fundus, but such a change in blood sugar levels was not demonstrated when the extract from the small intestine was injected. These results suggest that GI of the gastric fundus is close to pancreatic glucagon in respect of its metabolism and hyperglycemic activity.