SCANNING ELECTRON-MICROSCOPIC OBSERVATIONS ON GASTRIC MUCUS SECRETIONIN RATS, AND THE EFFECTS OF TETRAPRENYLACETONE

Mucus secretion in the gastric mucosa of rats was studied with a scann ing electron microscope. After stimulation, two types of mucus secreti on were observed: exocytosis and apical expulsion. Prolonged administr ation of tetraprenylacetone (TPA) significantly increased the number o f mucus-secreting cells in both the gastric corpus and antrum 12 h aft er the last administration of TPA. In the secreting cells, apical expu lsion was significantly more frequent among TPA-treated than in untrea ted rats. TPA also significantly increased the hexosamine concentratio n in both gastric corpus and antrum. These findings indicate that TPA stimulates both the content and the secretion of gastric mucus, and th at its secretion is chiefly through apical expulsion.