Electron-microscopic studies on morphological changes in the surface mucous cell during migration in the stomach of the golden hamster.

Morphological changes in the surface mucous cells in the gastric body of the golden hamster occurring during their movement from the lower to the upper portion of the gastric pit have been observed by using scanning as well as transmission electron microscopes. The cells have a wide base and a narrow apex in the lower and middle portions of the pit, while at the opening of the pit to the gastric lumen, they become taller and funnel-like in shape, and are characterized by well developed interdigitations and intermediate filaments sometimes associated with desmosomes. During this transformation of the cell contour, the nucleus moves towards the upper region of the cytoplasm, whereas the Golgi apparatus moves downwards to the infranuclear region. Then, there appear secondary lysosomes showing crinophagy and lipid droplets around or near the Golgi apparatus. Though the basal part of the cells is very small, no images of the detachment of the basal plasma membrane from the basal lamina could be seen even at the site of severe cell degeneration. The tall funnel-shaped cells showing these characteristics are located on the interfoveolar ridges of the underlying fibrous layer and line the free surface of the stomach. Therefore, the interfoveolar cells which have lost the activity of secretory granule production and are going to undergo physiological degeneration are thought to be highly differentiated elements as a covering epithelium to protect the underlying tissue, resembling in this respect the keratinocyte of the epidermis.