Cellular localization of endocrine cells in the adult pancreas of the house musk shrew, Suncus murinus: a comparative immunocytochemical study.

The right and left lobes of the pancreas in the house musk shrew, Suncus murinus, were found to be completely separated. A morphologic study of the pancreas in S. murinus in terms of the blood supplies and innervation of the right and left lobes was performed in our previous study. It revealed clearly different blood supply and innervation patterns in the right and left lobes, suggesting that the right lobe of the pancreas corresponded to the ventral pancreas, and the left lobe related to the dorsal pancreas. To test this perspective from the histology, in this study, we investigated the immunolocalization of the cells of Langerhans islets in the pancreas of the animal. The distribution of insulin-, glucagon-, somatostatin-, and pancreatic polypeptide (PP)-secreting cells of the right and left lobes of the pancreas was examined in 10 animals. The glucagon-immunoreactive cells were distributed in both the right and left lobes. The PP-immunoreactive cells were extremely abundant in the right lobe and distributed throughout almost all the islets of Langerhans in the right lobe. By contrast, in the left lobe, immunoreactive PP cells were absent in the islets of Langerhans, and only very few immunoreactive PP cells were scattered in the exocrine parenchyma in part of the specimens. Therefore, these findings support our previous studies, and showed that the right and left lobes of the S. murinus pancreas could be related to an embryological origin from the ventral and dorsal pancreatic primordium, respectively, and that the S. murinus pancreas is suitable as a new experimental model to study the development of the human pancreas.