[Suitability of specific staining methods for the estimation of beta cell volume in rat pancreas with normal and reduced insulin content].

Investigations were carried out on streptozotocin (SZ)-treated female Wistar rats (single i.v. injection of 30 mg/kg body weight) and control animals with normal pancreatic insulin content. After staining of the pancreatic slices with aldehyde fuchsin (AF), Victoria Blue (Ivic 1959), and FITC-labelled antiserum (indirect), the beta-cell volume was determined with a point sampling method. For control animals, all 3 selected beta-cell specific staining methods are equivalent. After reduction of the pancreatic and the beta-cell insulin content by SZ-treatment the sensitivity of the common histochemical methods is diminished in comparison to the immunofluorescence method. In normoglycemia SZ-treated animals (pancreatic insulin content about 30% of control values) 0.22% AF-stained beta-cells are demonstrable, after IVIC-staining 0.14% beta-cell volume is visible. In hyperglycemic SZ-treated rats (about 6% of pancreatic insulin content of controls) with AF-staining only 0.08% and with IVIC-staining 0.03% beta-cell volume could be measured whereas with fluorescence technique in both SZ treated groups 0.34% beta-cell volume is measurable. The reduction of pancreatic insulin content after the injection of 30 mg/kg SZ is caused by a reduction of the beta-cell volume and a diminution of the insulin content in the remaining beta-cells.