Effects of diet composition on the reactivity pattern to the zinc-iodide/osmium-tetroxide mixture of the rat pancreatic acinar tissue.

When adult rat pancreatic exocrine tissue is incubated in zinc-iodide/osmium-tetroxide (ZIO) mixture, 3 cell types are recognized depending their degree of impregnation: intensely impregnated (I-PAC), moderately impregnated (M-PAC), and non-impregnated (N-PAC) cells. Their distribution in pancreatic head was 8%, 46% and 46% respectively; whereas in the tail, it was 7%, 35% and 58% respectively. With the purpose to know whether those variations in ZIO-impregnation had some relation with the diet components, 7 groups of 30-day old male rats (n = 5 each) were maintained for 40 days with the following diets: control (C), high-protein (HP), low-protein (hP), high-lipid (HL), low-lipid (hL), high-dextrin (HD) and low-dextrin (hD) diets. Fragments of head and tail were incubated in ZIO mixture, embedded in epoxy resins and cut. Sections were examined unstained under a light microscope. The most striking features in the head were seen with hP, hL and particularly with HD diets. In tail tissue, the most relevant changes were seen with hP, hD and especially with HL diets. It is concluded that there could be a regional acinar cell populations related to preferential production of digestive enzymes in pancreatic head, body and tail, which would need to be further investigated.