Argentaffin granules in endocrine cells in human duodenal mucosa.

An attempt was made to gain ultracytochemical characteristics of the endocrine cells in the human duodenal mucosa. Bodian argyrophil and Fontana-Masson argentaffin reactions were applied to the blocks of the tissue. The ultracytochemistry showed that the secretion granules of all morphological types of the endocrine cells were precipitated with both the argyrophil and argentaffin silver grains in varying intensity. The endocrine cells containing uniformly round secretion granules tended to show a heavy precipitation with the argyrophil silver grains in contrast to a light precipitation with the argentaffin silver grains. The endocrine cells containing pleomorphic secretion granules were heavily precipitated with both the argyrophil and argentaffin silver grains. The findings of the present study suggest that the duodenal endocrine cells represent a single cell type in respect to 5-hydroxytryptamine metabolism, but differ in their metabolism of other polypeptide hormones.