Electron Microscopic Observations on Cell Proliferation and Differentiation in the Gastric Mucosa of the Mouse

Abstract

After an injection of ³H-thymidine, the renewal of epithelial cells in the gastric mucosa of normal adult mice was studied by simple electron microscopy and electron microscopic autoradiography.
1. Undifferentiated cells are present in the isthmus as a common matrix for surface mucous cells and mucous neck cells. Their differentiation to chief and parietal cells seems probable but could not be evidenced. Undifferentiated cells are proliferative in the isthmus.
2. Immature surface mucous cells have mitotic activity in the isthmus and in deeper parts of the pit. They grow mature as they migrate towards the surface of the mucosa.
3. Mucous neck cells, especially in their immature stage, are proliferative in the isthmus and in the neck. They migrate from the isthmus to deep parts of the neck.
4. Primitive chief cells are first identified in the upper parts of the glandular base. They have mitotic activity and become mature with downwards migration.
5. Parietal cells grow mature with their migration from the isthmus towards the base. Mitotic activity of parietal cells could not be confirmed.
6. There were no finding suggesting the transformation from mucous neck cells to chief and parietal cells.
7. Ultrastructural changes during the differentiation of each cell type were described.