[Ultrastructure of endocrine cells in the gastric fundal glands at different seasons of the year].

Endocrine cells of gastric glands of Citellus erythrogenus Brandt were studied during various seasons of the year by electron microscopy. ECL, EC, D and D1 cells having different structure of granules were detected. The slightly changed, weakly functioning cells as well as the cells of different alteration degree (up to destructing) were found in hibernating rodents. The presence of actively functioning EC-cells over this period confirms an opinion concerning the influence of peripheral serotonin on the hibernation mechanism. On the 3d--4th day of awakening pronounced activation of endocrine cells, their rejuvenation and normalization of cell ultrastructure, completed two weeks after awakening, were noted.