Morphometric studies on the juxta-insular and tele-insular acinar cells of the pancreas in normal and streptozotocin-induced diabetic rats.

In the present study on the exocrine pancreas, stereological techniques were applied at the level of electron microscopy to confirm morphological differences between juxta-insular and tele-insular acinar cells of normal rats and to evaluate the effect of B cell secretion on these differences in streptozotocin-diabetic rats. As no similar data have been previously published, we conducted a systematic sampling analysis with special reference to the acinar cell volume, the granule content and the nuclear size. In the normal rats, the juxta-insular acinar cell had an average volume of 918 microns3 and contained 420 zymogen granules which occupied 10.2% of the cell. In tele-insular acini, the average cell volume was estimated at 755 microns3 and the cell contained 231 zymogen granules which amounted to 6.8% of the cell. The juxta-insular acinar cell was 18% larger in size and contained 45% more zymogen granules, but no difference was observed in the size of zymogen granules. In addition, the numerical density of cell nuclei was slightly larger in the tele-insular acini in spite of the similarity in the volume density and diameter of the nuclei in the cells of the two areas. In the streptozotocin-induced diabetic rats, no differences were observed in the cell volume and the zymogen granule content between the juxta- and tele-insular acini. These data suggest that the morphological inhomogeneity in the pancreatic acini is caused by the influence of B cell secretion on the activity of the juxta-insular acini.