Localization of APP, a postulated new hormone, to a pancreatic endocrine cell type

Research paper by L. -I. Larsson, F. Sundler, R. Håkanson, H. G. Pollock, J. R. Kimmel

Indexed on: 01 Dec '74Published on: 01 Dec '74Published in: Histochemistry


APP is a polypeptide which has been isolated from avian pancreas and shown to exert pronounced biological effects. Immunofluorescence revealed APP to be present in the cytoplasm of numerous cells disseminated in the exocrine parenchyma of the chicken pancreas. The APP cells were polygonal or spindle-shaped and often had elongated processes in between the exocrine cells. The APP cells were particularly numerous at about hatching. They did not stain with methods demonstrating the three well-known islet cell types (A, B and D). The cells had the capacity to take up and decarboxylate l-dopa, a property shared with many polypeptide hormone-producing cell systems. Ultrastructurally, the APP cells had the appearance of polypeptide hormone-producing cells in that they contained numerous cytoplasmic granules Their granular morphology showed some resemblance but was not identical to that of the D cells.