Pancreatic islets of malnourished rats: quantitative histologic and electron microscopic findings

Young rats were maintained for three weeks on a low-protein diet. These animals developed many of the features of human protein-calorie deficiency, including dextrose intolerance and diminished insulin release. Quantitative histologic and ultrastructural studies showed that malnourished rats had (1) a reduced total pancreatic islet volume, and (2) a preponderance of pale granules in the B cells. It is suggested that pale B granules may contain increased amounts of insulin, which accumulate in the cells because of defective insulin release. The mechanism responsible for this has not been elucidated.