Studies in the diabetic Chinese hamster: Electron microscopy of pancreatic islets.

Electron microscopic studies were performed on pancreatic islets of normal, genetic, nondiabetic Chinese hamsters and of diabetic animals of all degrees of severity. The ultrastructural appearance of the islets of normal hamsters did not differ from that of normal rats and mice. The islets of the profoundly diabetic animals could be distinguished because of the magnitude of beta cell glycogen infiltration, frequency of beta cell necrosis and decreased number of surviving beta cells. Islets of hamsters with spontaneous remission from diabetes contained increased numbers of hyperfunctioning beta cells. Surviving beta cells of all diabetic hamsters revealed ultrastructural evidence of enhanced insulin synthesis and secretion but revealed no evidence to suggest that they were insensitive to physiological stimuli or incapable of insulin synthesis. Spontaneous remission among diabetic Chinese hamsters could thus be explained, in part, on the basis of enhanced beta cell replication resulting in an increased insulin synthetic capacity. [ABSTRACT FROM AUTHOR]