Self-replication of somatostatin cells in the antral mucosa of rodents

Abstract

The possibility that antral somatostatin cells have a self-replicating activity was studied in 3 species of rodents: mice, rats and guinea pigs, after a flash tritiated thymidine injection. The immunocytochemical staining of somatostatin cells, using specific antiserum was combined with radioautographic procedures. The labeling index for somatostatin cells-and for gastrin cells identified on serial sections-was established after counting a large number of cells at the optical microscope level, on parallel tissue strips removed throughout the entire antrum. A significant percentage of the somatostatin cell population synthesized DNA. Values were similar for the 3 species of rodents ranging from 0.8 to 1.1%, that is slightly higher than the percentage of labeled gastrin cells which was 0.6-0.7%. After a 36-h continuous infusion of radioactive precursor in 1 rat, the labeling index observed remained low; 2.33% for somatostatin cells and 1.68% for gastrin cells. Colchicine injection in mice allowed the observation of mitotic figures in well differentiated somatostatin cells. Four hours after that injection, the mitotic index was estimated roughly at 0.3%. Evidence was presented that in rodents a fraction of the antral somatostatin cell population is capable of dividing, similar to the situation in gastrin cells.