Abstract
The enteroendocrine cells of the mouse duodenum were examined in the light and electron microscopes by comparing Epon sections stained by Gomori's silver methenamine with adjacent sections stained by Masson's ammoniacal silver nitrate, iron hematoxylin or uranyl acetate and lead citrate. Furthermore, the granules present in the enteroendocrine cells stained with silver methenamine were investigated in the electron microscope: their shape was defined as either spherical or nonspherical and, in either case, their density was measured by cytophotometry. The comparison of adjacent sections of mouse duodenum by different techniques indicates that the granules of all enteroendocrine cells are stained by iron hematoxylin, whereas those of about 94% of the cells are stained by silver methenamine. Since silver methenamine stains exactly the same cells as ammoniacal silver nitrate, it may be used as a test of argentaffinity. It is concluded that about 94% of the enteroendocrine cells are argentaffin and about 6% are nonargentaffin. The argentaffin cells display a wide spectrum of granule shape. Nearly all of the granules of a cell may be spherical or nearly all nonspherical or, more commonly, there is a fair number of both kinds. In the few cells which are not argentaffin, over 70% of the granules are spherical. After silver methenamine staining, the mean density of spherical and nonspherical granules is statistically equal within any given cell. Yet, when cells are compared to one another, the mean density of the granules, and therefore the argentaffinity, increases with the proportion of nonspherical granules. It is concluded that, in the mouse duodenun, argentaffinity is most pronounced in the cells with irregular nonspherical granules, but it is by no means confined to such cells. Moreover, the argentaffinity as well as the shape of the granules varies within wide limits.