| Abstract: | Summary The pancreatic islet in the mouse has a highly complex and heterogeneous structure. It contains Aa, Ab, Ac, B, C, D, E, and F cells. The classification of cell types is primarily based on the shape, size and electron opacity of secretory granules and on the spatial relationship of the granules to their unit membranes. Morphological evidence is supported by a statistical analysis of the size distribution of granules and of their membranes. Experimental immunization of mice with insulin, provides additional data to support the existence of eight different cell types in the islet of the normal animal and reveales marked immunological stimulation of B cells, secondary stimulation of Aa, D and F cells, atrophy of Ac cells and hyperplasia of C cells. It is proposed that corresponding cell types exist in other mammals and man. The experimental insulin immunization process appears to perform an immunofunctional analysis of the islet, and suggests that in mice the Aa, D and F cells might be involved in cell energy supply. Lipocaic and some pancreatic factors with insulin-like activity (NSILA) will likely find their morphological equivalents. It is proposed that chemical solubility techniques represent the most promising avenues of approach to the isolation of secretory products from the endocrine pancreas, and that the assay of these extracts should primarily be conducted at the cell level.Dedicated to Prof. Dr. med. W. Masshoff on his 60th birthday.The author is indebted to Dr. med. H. J. Stolpmann for guidance in applying the techniques of electron microscopy and wishes to express his special appreciation to Mrs. Marjanne Hinz for her valuable assistance in completing different aspects of this work and for her competent technical aid. |
