ABNORMAL PROLIFERATION OF PANCREATIC ENDOCRINE CELLS IN BEAGLE DOGS

抄録

Of 164 dogs used in routine toxicity studies, seven male and three female Beagle dogs 6 to 17 months of age were found to have spontaneous proliferation of pancreatic endocrine cells. The changes consisted of various combinations of irregular-shaped islets, the budding of endocrine cells from ductal epithelia, beta cell nesidioblastosis composed of a few beta cells, focal adenomatous proliferation of endocrine cells, and prominent ductulo-insular complexes. The proliferated endocrine cells were slightly enlarged containing numerous minute granules in their cytoplasm and were interspersed with ductular cells. Immunocytochemically, a moderate increase was seen in beta and delta cells, and pancreatic polypeptide cells were frequently observed in the nesidioblastic lesions, suggesting that nesidioblastosis might have occurred as a regenerative change stimulated by the destruction of exocrine tissue.