A mucosal defect was made cryosurgically in the mucosa of the fundus of the rat stomach. The morphology and cell kinetics of the regenerated mucosa were studied 50, 100 and 200 days after operation. At all three time points the mucosal defect was completely covered with the regenerated epithelium. The regenerated mucosa was composed mostly of mucinous glandular structures, and remained of a pseudopyloric type even 200 days after operation.
The pseudopyloric glands consisted of two different kinds of cells-mucin-containing cells and endocrine cells. The former cell type lacked the characteristics of typical mucous cells, having instead cytological features intermediate between those of mucous and serous cells, and they resembled true pyloric gland or Brunner’s gland cells. By3H-thymidine autoradiography it was shown that the mucous-serous cells of these pseudopyloric glands are produced from proliferating cells confined to the isthmus region. Their half life was estimated to be 5–6 days. If cell turnover reaches a steady state in the regenerated glandular structures, they would be renewed continuously; on this basis it is suggested that pseudopyloric glands may be persistent mucosal structures in the fundic region of the stomach following ulceration and mucosal regeneration.