Effect of Pentagastrin on Gastric Mucosal Cells Grown in Tissue Culture

Numerous studies have shown that chronic administration of pentagastrin leads to parietal cell hyperplasia in the rat. This indicates that gastrin may have a proliferative as well as a secretory effect on gastric mucosa. Primary explants of rat and human gastric mucosa from the oxyntic gland region were cultured in T flasks. The cultures were not disturbed until outgrowth of fibroblasts and epithelial cells had occurred. This latent period lasted approximately 7 days. Either pentagastrin (to a concentration of 0.5 μg per ml) or an equal volume of saline was then added daily to the cultures and subsequent subcultures. Control (saline) cultures showed rapid growth of fibroblasts and ultimate loss of epithelial cells. Fibroblastic outgrowth was inhibited and epithelial cell proliferation was stimulated in the cultures receiving pentagastrin. At confluence the mitotic index of subcultures treated with pentagastrin was more than twice that of the control cultures. Total protein of subcultures receiving pentagastrin was twice that present in saline-treated subcultures which had been started with an equal amount of inoculum and otherwise identical to the pentagastrin-treat ed flasks. Electron microscopic observations have defined a primitive epithelial populace in the pentagastrin-treat ed cultures presenting as a composite of the anatomical features seen in the differentiated gastric mucosal cell flora. The results imply that gastrin has a direct proliferative effect on gastric mucosal epithelium.