Insulin and Glucagon Secretion by Pancreatic Islets from Nondiabetic and Diabetic Sand Rats (Psammomys obesus)

Abstract. The secretion of insulin and glucagon was investigated in pancreatic islets from diabetic and nondiabetic sand rats of similar age and weight. The metabolic characterization was based on an intraperitoneal glucose tolerance test. Compared to nondiabetic animals diabetic sarid rats had a diminished insulin content in their islets and a decreased insulin secretory response to glucose, glyceraldehyde and theophylline. Diazoxide inhibited insulin release in diabetic as well as in nondiabetic sand rats whereas mannoheptulose was effective only in the nondiabetic rats. There was no significant difference in glucagon content between the two groups. The glucagon secretion by pancreatic islets of diabetic animals was not suppressed by glucose, as in nondiabetic sand rats islets, but by glyceraldehyde. This indicates that the sensitivity to glucose rather than the suppressibility of glucagon release was altered.