Ultrastructure of pancreatic light and clear cells in normal and transplanted tissue fragments in the anterior eye-chamber of rats.

The ultrastructure of pancreatic light and clear endocrine cells in normal and transplanted tissue fragments in the anterior eye-chamber of rats was described by electron microscopy. Compared to the dark cells, the light cells contain a conspicuously poorly stained cytoplasmic ground substance with varying number of rough endoplasmic reticulum cisterns and secretory granules. The quantities of these two organelles are inversely proportional to each other. "Light" alpha, beta, delta and pancreatic polypeptide cell-types were identified in normal and transplanted tissue. Out of these, the light alpha cell is the most commonly occurring. The "clear" endocrine cells are much fewer in number than the light cells. They contain well stained cytoplasm with numerous low electron density vesicles and few secretory granules. There is no ultrastructural difference between the light and clear cells in normal and in transplanted tissue for 77 and 534 days. The occurrence of light and clear cells in the transplanted tissue shows that these transplants behave morphologically like normal tissue. These cell types might be related to the different stages of secretory granule synthesis and maturation.