Size and number of nuclei differ in normal and neoplastic acinar cells from rat pancreas

Acinar cells were isolated by enzymatic digestion from normal pancreas and from azaserine-induced atypical acinar cell nodules and a transplantable acinar cell carcinoma. Normal acinar cells were predominately binuclear, with abundant cytoplasm. They were 10-24 micron in diameter, with a size distribution skewed toward smaller sizes but with a peak at 18 micron. Cells were isolated from 41 enucleated nodules varying in weight from 1.1 to 200 mg. These cells were predominantly mononuclear, with a more uniform size than normal cells and a peak at 9 micron diameter. Cells from all nodules studied were grossly similar, and there was no relation between nodule size and the degree of mononucleation. Cells from the transplantable tumor were small, with little cytoplasm, and were almost exclusively mononuclear. The extent of binucleation in normal and microscopic atypical acinar cell nodules was also studied in sections from the pancreas of rats injected with azaserine 4 months before killing. Nuclear and cell counts in these sections confirmed that binucleation is more frequent in normal than in nodule tissue. These studies emphasize the high degree of binucleation found in normal pancreatic acinar cells. They demonstrate the feasibility of using cell separation techniques to obtain preparations of acinar cells from normal and neoplastic pancreatic tissue for studies of functional and morphological differences in these cells.