Cytology of islet cells in alloxan diabetic rabbits.

SETao A. BENcosmF, M.D. From the Department of Patkology, Patkological Institute, McGill University, Montreal, Quebec, and the Department of Pathology, Queen's University, Kingston, Ontario Most authors agree that after the injection of alloxan and the consequent destruction and disappearance of beta cells, the pancreatic islets contain numerous non-granular islet cells.1 These have been interpreted as agranular beta cells or agranular cells of an unspecified type. In contrast to our knowledge of the fate of the alpha and beta cells in alloxan diabetes, very little is known about that of the delta cell.56 Aside from the description of Conn and Hinerman7in a case of hypoglycemia treated with alloxan in a patient suffering from an islet cell tumor, and the brief discussions by Cavallero8 and Verne,9 no specific mention of the delta cell in alloxan-treated animals or man has been found. Some workers have studied the Golgi apparatus and/or the mitochondria of islet cells in order to delineate the morphologic structure and nges related to insulin secretion.1-13 The study of the Golgi apparatus and the mitochondria of islet cells has led other workers to postulate the presence of transitional forms between acinar and islet cells.1'15 While the histologic techniques employed by these investigators gave a positive impregnation of the Golgi apparatus, they did not permit an accurate identification of the various types of islet cells. The origin of new islet cells of each type and the question of their interconvertibility in alloxan diabetes are subjects which remain unsettled. Some workers have reported on the formation of new alpha and beta cells from acinar cells.13"6-'8 Others have stated that the newly formed beta cells are derived from the ductular epithelium.7"18-21 Berthoud,18 in agreement with Ferner,' reported that alpha cells are transformed into beta cells, while others 8.2123have stated that this has never occurred in their experience. In previous investigations on the histogenesis of the pancreatic islet of the rabbit, with methods capable of demonstrating the three types of islet cells as well as their respective cytoplasmic organelles in a single section, it was found that cells of each of these types were derived independently from duct cells and were not interconvertible.24 In view of this finding, it appeared that a study of the changes in the