Effects of a protein-free diet on the rat stomach.

The effects of a protein-free diet containing a mixture of free amino acids on the stomach were studied using male Wistar strain rats. In the forestomach, thickening of mucosa and hyperkeratosis appeared and papillomas frequently developed, but they did not occur in the control rats fed a semipurified diet. Mucous neck cells increased and parietal cells and chief cells decreased in the fundus. Goblet cells occurred in the antral glands, and intestinal metaplastic glands developed in the late stage of the experiment. The number of deoxyribonucleic acid-synthesizing cells in the glandular stomach was significantly higher than that of the control. Moreover, in the antrum, somatostatin-producing cells increased in the early stage and gastrin-producing cells decreased in the late stage. These results suggest that dietary protein might play a crucial role in the differentiation of gastric epithelium and the development of intestinal metaplasia in the stomach.