Correlative morphometric and biochemical study on pancreatic amylase in normal and streptozotocin-diabetic rats

The number, volume, and size of zymogen granules in pancreatic acinar cells of normal and streptozotocin-diabetic rats were measured using stereological techniques. These morphometric data were then correlated with the amylase activity of the acinar cells. In the normal rats, the acinar cells had a mean volume of 1,253.5 microns 3 and contained 343 zymogen granules, which occupied a volume of 103 microns 3 of the cell (8.28%). In the diabetic rats, the mean acinar cell volume was estimated as 1,017 microns 3 and the cell contained 220 zymogen granules, which occupied a volume of 55.8 microns 3 (5.38%). The cell volume and zymogen granule number and volume were 19, 36, and 46%, respectively, more in normal rat pancreas, while no difference in the size of zymogen granules between normal and diabetic rats was observed. On the other hand, the volume density and numerical densities of acinar cell nuclei were slightly larger in the diabetic rats, but no differences in the nuclear size between normal and diabetic rats were recorded. Biochemically, the amylase activity of diabetic rat pancreas was 37% less than that of normal rats. The present results indicate the impairment of pancreatic amylase production in streptozotocin-diabetic rats, and the correspondence between the morphometrical and the biochemical data indicates that amylase is processed intracellularly in membrane-bound compartments.