Insulin-, glucagon-, and somatostatin-containing cells, identified by immunofluorescent staining, were quantitated morphometrically in sections of pancreas obtained from diabetic and nondiabetic humans and rats. Both the volume density and number of somatostatin-and glucagon-containing cells were The other diabetic pancreas was obtained from a 31-yearold white female with a 29-year history of juvenile-type diabetes who died of renal insufficiency. Grossly, the pancreas was indurated and microscopic examination revealed acute pancreatitis. Islets were sparse and small, consisting largely of A-cells. No B-cells were noted.The four nondiabetic pancreases were obtained from encephalographically dead kidney donors in Geneva and Dallas in accordance with local regulations.Streptozotocin Diabetic and Nondiabetic Rats. Pancreases were obtained from four normal control rats and four rats with 16 months of diabetes produced by a single intravenous injection of 45 mg of streptozotocin per kg of body weight. These rats never required insulin treatment, but all were glycosuric at the time of sacrifice.Immunofluorescent Staining Techniques. The indirect immunofluorescent technique of Coons et al. (25) was employed with use of a rabbit anti-somatostatin serum (a gift of Dr. M. P. Dubois) at a dilution of 1:50, highly specific rabbit anti-glucagon serum 15K at a 1:20 dilution, and a guinea pig anti-insulin serum (a gift of Dr. P. H. Wright) at a 1:50 dilution. Anti-rabbit or anti-guinea pig gamma globulin labeled with fluorescein isothiocyanate (Pasteur Institute, Paris) was employed as the second antibody.Control experiments were performed using the specific antiserum absorbed with the corresponding antigen, 200,g of cyclic somatostatin (a gift of Drs. J. Rivier and R. Guillemin), 50 jig of glucagon, or 2 units of insulin per ml of undiluted antiserum. After removal of the paraffin, sections were rehydrated and incubated for 2 hr with anti-somatostatin, anti-insulin, or anti-glucagon serum. After rinsing in phosphate-buffered saline, the sections were incubated with the fluorescein-labeled antibody for 1

By immunofluorescence, somatostatin-, glucagon- and insulin-containing cells are localized in serial sections of the pigeon pancreas. The distribution of the somatostatin immunofluorescent-cells corresponds to that of the D-cells (A1-cells), which are particularly numerous in this animal species. This observation, coupled with the finding of D, A and B-cells at the ultrastructural level, indicates that the D-cell is responsible for the secretion of somatostatin.

No abstract

An immunocytochemical technique using specific antiglucagon serum reveals the presence of glucagon-containing cells situated exclusively in the oxyntic glandular mucosa of the dog stomach. Electron microscope examination of the mucosa demonstrated endocrine cells containing secretory granules with a round dense core surrounded by a clear halb, indistinguishable from secretory granules of pancreatic A cells. Like the alpha granules of pancreatic A cells, the granules of these gastric endocrine cells exhibited a peripheral distribution of silver grains after Grimelius silver staining. Moreover, the granules of these cells were found to be specifically labeled with reaction product, using the peroxidase immunocytochemical technique at the ultrastructural level. Accordingly, these cells were named gastric A cells.These data suggest that the gastric oxyntic mucosa contains cells indistinguishable cytologically, cytochemicaUy, and immunocytochemically from pancreatic A cells. It is believed that gastric A cells are responsible for the secretion of the gastric glucagon.

Evidence is presented that somatostatin-containing cells are present in the gastro-intestinal tract of the dog. Thus immuno-fluorescent cells were detected by the use of antiserum to cyclic somatostatin. These cells were mainly encountered in the antral mucosa and in the neighbourhood of gastrin-producing cells. No cross reaction was observed between gastrin and somatostatin. It is suggested that locally produced somatostatin controls gastrin secretion, and, more generally, that somatostatin-containing cells, multifocally distributed, modulates secretion of a large number of glands.