Glucose-induced insulin secretion and insulin sensitivity of peripheric organs of Egyptian sand rats before manifestation of diabetes.

In Egyptian sand rats (Psammomys obesus) fed with native food and a low caloric vegetable diet after capture it was possible to study endocrinologic and metabolic changes of the early stages during the progression to diabetes. According to body weight gain and fasting blood glucose the animals were differentiated into two groups classified as basic and protodiabetic group, respectively. Isolated pancreatic islets as well as the perfused pancreases of sand rats responded to low concentrations of glucose with high insulin release during early stages of the development to diabetes. Changes in the insulin content of the islets could not be detected at this time although in the B-cells of the protodiabetic animals a degranulation was visible. During these early stages of the development to diabetes the in vitro insulin action on glucose utilization in soleus muscle and especially in epididymal fat pads as well as the basal glucose metabolism in adipose tissue were low. This strikingly reduced utilization of glucose by adipose and muscle tissues may be a factor which challenges the B-cell.