Immuno- and enzyme-cytochemical studies on the pancreatic D-cells in the chicken following vagotomy.

To study the appearance of polymorphic, dense multivesicular body-like structures (MBLS) occurring in the D-cells of pancreatic islets following abdominal vagotomy in the chicken, the D-cells were evaluated by means of quantitative electron microscopy, identified by immunogold labeling and characterized by a method of enzyme cytochemistry. Following vagotomy, secretory granules of the pancreatic D-cells decreased significantly in number, whereas MBLS increased significantly in number. the mean area of the cell, nucleus and mitochondria displayed no significant changes. MBLS were rarely labeled for somatostatin when subjected to immunogold staining. MBLS arranging along the Golgi stacks may possibly be formed in the Golgi apparatus. consequently, it seems unlikely that MBLS are secondary lysosomes revealing crinophagy. Some MBLS showed acid phosphatase (AcPase) activity, although the direct fusion of primary lysosomes exhibiting AcPase activity with MBLS was seldom observed. As a result, it is possible that MBLS may be a kind of modified form of secretory granules and that they may be destroyed by lysosomes under the storing condition, judging from the AcPase reaction.