Electron Microscopy of the Pancreatic Islets of the Rat: Effects of Prolonged Insulin Injections

The electron microscopical changes of the pancreatic islets of rats were studied during the phase of transient diabetes and during recovery, following a prolonged period of insulin injections.

The most characteristic changes, besides the severe degranulation of the beta cells, were the “inactivity” of the Golgi complex and the absence of special spheroidal bodies from its vicinity. Evidence is presented that these satellite bodies may represent pregranules. Differences in the formation of granules in the Golgi area of the alpha, beta and acinar cell are illustrated and discussed.