The physicochemical nature and biological function of extrapancreatic immunoreactive glucagon

The physicochemical nature and biological function of extrapancreatic immunoreactive glucagon in the plasma of totally pancreatectomized dogs were studied. The experimental animals were divided into two groups. Group A received only total pancreatectomy while group B had total pancreatectomy plus total gastrectomy. The blood was taken from both groups of dogs and glucagon was extracted using acid alcohol. The amount of IRG contained in the plasma extract was measured and the glycogenolytic activity of the plasma extract was studied using a rat-liver perfusion. The plasma extract from group A showed almost the same glycogenolytic activity as a commercial beef-pork glucagon but the plasma extract from group B manifested no glycogenolytic activity. The plasma from both groups were fractionated using column chromatography and their physicochemical nature was compared. The IRG in the plasma from group A was fractionated into 3 types, molecular weight 9000, 7000 and 3500, while the IRG in the plasma from group B was found to be of M.W. 9000 and 7000. These results lead to the following conclusions: 1) Extrapancreatic IRG in the plasma is fractionated into three types. 2) The glycogenolytic activity of extrapancreatic IRG is assumed to depend on the IRG fraction of molecular weight 3500. 3) Most of the extrapancreatic IRG fraction of M.W. 3500 originates in the stomach.