Expression of S-100 protein in intercalated duct cells of bovine pancreas

Although Mutoh et al. have found intercalated ducts in the pancreatic islets of avians, including the chicken, moorhen (Gallinula chloorpus), and Japanese quail (Coturnix coturnix japonica), and even demonstrated the functions of intercalated duct cells in pancreatic islets, to our knowledge, there have been only a few reports on the relationship between intercalated ducts and islets in mammalia. Accordingly, in this study, we investigated whether intercalated ducts are morphologically related to the islets of cattle, by using S-100 protein as a ductal cell marker for immunocytochemistry and examining the ultrastructure of intercalated ducts and islets electron-microscopically. The results revealed intercalated ducts that reacted positively for S-100 protein within and near islets, with approximately 12% of the islets having intercalated ducts in the vicinity and approximately 1.5% containing intercalated ducts within them. Ultrastructurally, intercalated ducts were also seem to be closely related to the islets. In conclusion, the results of the present study indicate that a close relationship exists between intercalated ducts and islets.