The islets of Langerhans in pancreatic fibrosis

A survey is given of earlier views on the occurrence of diabetes and decreased glucose tolerance in cystic fibrosis of the pancreas, as well as on the structure of the islet tissue in this disease and in experimental fibrosis of the pancreas. Intravenous glucose tolerance tests were performed in three patients with cystic fibrosis. of the pancreas, and normal glucose tolerance curves obtained. Fibrosis of the pancreas was produced experimentally in rabbits by ligation of the pancreatic duct. In eight of nine such animals, the glucose tolerance was normal. Histologically, the pancreas exhibited total acinar atrophy, with cystic dilatation of the ducts, between which numerous small islets of Langerhans of fetal type were compressed. The general picture was similar to that seen in the fetus and in cystic fibrosis of the pancreas. Quantitative determinations of the islet volume showed a great reduction in size of the islet tissue, due chiefly to a marked decrease in area of the individual islets. The alpha-to-beta cell relations were, however, normal. The results are discussed, and compared with those in alloxan-diabetic animals and with animals with experimentally produced hypertrophy of the pancreas. In the latter the islet tissue hypertrophies as well (Fig. 7). The prenatal relations between the exocrine and endocrine tissues of the pancreas may also exist postnatally. The resistance to the diabetogenic effect of alloxan present in animals with the pancreatic duct ligated seems to be associated with the immature, fetal structure of the islet tissue in acinar fibrosis.