Argentaffin Cells of the Pancreas

Abstract

In the pancreas of the dog, Lasowsky has described the existence of argentaffin cells in the acini and in the islands of Langerhans. These cells do not reduce the silver solutions in the same way as the true argentaffin cells of the digestive tract; they remain unstained when placed in the ammoniacal silver solution but show up clearly after block silver treatment. During an investigation of the histogenesis of the pancreas, we have been able to verify the descriptions of Lasowsky and to extend the facts to the human pancreas and to the pancreas of the calf, the pig and the chick; the Roger's silver impregnation, in addition to its nerve demonstration usefulness, brings the argentaffin cells into clear evidence. The pancreas of a 12 mm. pig embryo shows numerous silver-stained cells; they represent the first histological differentiation in the solid epithelial cords, which later become the primary pancreatic ducts from which the islands and the acini will differentiate. The argentaffin cells can be found at all stages of development of pig and calf embryos and exist in the acini, the islets and the walls of the pancreatic ducts. In the acini, the argentaffin cells are found between the secretory cells; they usually are pyramidal in shape, with their base extending along the basal part of the neighboring cells. The basal part of the cytoplasm is filled with granules, while these seem to be less closely grouped in the apical pole. Sometimes these cells have a multipolar aspect and send out granular processes which can be followed for a considerable distance (20 micra). In the islands, the argentaffin cells show a smaller number of granulations which are scattered in the cytoplasm; the silver staining property appears to be uneven and one might consider the existence of intermediate stages between the clear and the argentaffin cells.