Immunocytochemistry of Vitamin D-Dependent Calcium Binding Protein in Chick Pancreas: Exclusive Localization in B-Cells.*

The vitamin D-dependent calcium binding protein (CaBP) is localized by light microscopic immunocytochemistry in the chick pancreas. CaBP immunoreactive material was found in islet cells, whereas the exocrine pancreatic tissue gave no immunostaining. In a series of consecutive tissue sections stained for CaBP, insulin, somatostatin, glucagon and avian pancreatic polypeptide, the cellular pattern of CaBP staining corresponded to that of the B-cells. The immunocytochemical localization of the vitamin D-dependent CaBP in the insulin-producing B-cells adds further evidence to the concept that vitamin D has an effect on B-cell functions.