人, 膵B細胞におけるProline rich peptide P-Cの存在

: It is well known that there are functional and morphological similarities between the salivary glands and the pancreas. Amylase, kallikrein and glucagon are present in both tissues. Morphological similarities of the two tissues have been observed by using a light and electron microscope. In order to examine the pathophysiological relationship between the pancreas and the salivary glands, an immunohistochemical study using antisera against proline-rich peptide P-C, which was recently isolated from human whole saliva, was carried out on the human salivary glands and the pancreas. Peptide P-C like immunoreactivity was found not only in the salivary glands but also in the pancreatic islets. Furthermore, observation of serial thin sections immunostained with insulin, glucagon, somatostatin, PP antisera and antisera against peptide P-C revealed that peptide P-C like immunoreactivity-containing cells were identical to insulin containing B-cells. As the antisera against peptide P-C did not have any cross-reactivity to other kinds of peptide including insulin, glucagon, somatostatin, pp, VIP, human C-peptide and kallikrein, the present finding suggests that peptide P-C like immunoreactivity is present in the B-cells independently of insulin and proinsulin. The finding seems to be a new addition to the lists of proof which support the presence of a pathophysiological relation between the salivary glands and the pancreas. Although it seems likely that peptide P-C like immunoreactivity in the pancreatic B-cells may play some role in the function of the B-cells, since this material was present only in the B-cells among four kinds of cells in the pancreatic islets, its exact pathophysiological role remains to be elucidated.