[Participation of the stomach and small intestine in the mechanism of insulin secretion following oral glucose administration].
In chronic experiments on 22 dogs, four of them having fistulas of oesophagus, stomach, and duodenum combined with artificial dissociation of stomach from duodenum, the per os and intraduodenal administration of glucose increased concentration of glucose and immunoreactive insulin in the peripheral blood, while intrastomach administration of glucose increased the immunoreactive insulin concentration alone. The data obtained suggest three phases of insulin mobilization: the first is due to neural mechanisms and occurs at the moment of contact between glucose and mucosa of the mouth, stomach, and duodenum; the second phase seems to be due to enterohormones and is activated by the contact between glucose and mucosa of the mouth, stomach, and duodenum; the third phase is associated with resorptive hyperglycemia which directly activates the B-cells.