Abstract
We performed histological and histochemical investigations on the so-called cardiac and fundic glands in the swine, to clarify the characteristics of these glands.
1. Glands, distributed in the immediate vicinity of the proventriculus, are regarded as cardiac glands, and are apparently different from the fundic glands.
2 Immature chief cells in the fundic glands lose their PAS-positive substance and differentiate into mature chief cells, which form a well-developed reticulate framework in the supranuclear cytoplasm. However, these changes are not observed in the cardiac glands.
3. Fairly small, claret pepsinogen granules are contained in the fundic gland mucous neck cells and immature chief cells. The same granules in fundic gland mature chief cells are coarse and dark blue.
4. The cardiac glands also contain many small, claret pepsinogen granules.
5. We speculate that the PAS-positive chief cells with no reticulate framework and containing small, claret pepsinogen granules are in the undifferentiated stage.
6. Based on the above facts, the so-called cardiac glands are considered to be undifferentiated fundic glands. That is the cardiac glands do not exist in the swine.
7. Weak and strong acid mucopolysaccharide are found in the upper portion of the cardiac glands and neutral mucopolysaccharide are found throughout the cardiac glands. However, the cardiac glands of the swine are not simple mucous glands; their main function is to secrete pepsin.
