Glucose and insulin in the regulation of glucagon release from the isolated perfused dog stomach.

The respective roles of glucose and insulin in the regulation of glucagon release from the canine stomach were investigated using an isolated blood-perfused preparation. At normal blood glucose and plasma insulin levels, the stomach released small amounts of glucagon. Such basal gastric glucagon release was not modified by hyperglycemia. In contrast, gastric glucagon release was increased by hypoglycemia or 2-deoxy-D-glucose-induced cytoglycopenia. Antibody neutralization of basal circulating concentrations of insulin (10 +/- 1 microU/ml) doubled the stimulation induced by hypoglycemia alone. It is concluded that: 1) suppression of gastric glucagon release is observed with very low concentrations of insulin; 2) basal gastric glucagon release is not further suppressed by hyperglycemia; and 3) that hypoglycemia and cytoglycopenia stimulate gastric glucagon secretion.