Insulin secretion by isolated islets of alloxan diabetic rats

Glucose-induced insulin secretion was studied in isolated pancreatic islets from one to twelve week alloxan diabetic rats is 1/4 to 1/7 that of the controls. Insulin secretion by alloxan diabetic rat islets progressively diminishes with time after alloxan injection. The individual isolated islet gives insulin secretion of 54%, 27%, 15% and 19% of the controls at one, two, four and twelve weeks respectively. The estimeated total insulin secretion by all of the isolated islets from each pancreas is 11.0%, 5.4%, 3.1% and 2.8% of the controls by the one, two, four and twelve week alloxan diabetic rats. These results indicate beta cell loss is progressive with time until four weeks after alloxan injection when glucose-induced insulin secretion is characterized by a flat hyporesponsive curve indcative of completely deficient insulin secretion.