Protein synthesis inhibitors and gastric acid secretion.

The involvement of de novo protein synthesis in acid secretion by the in vitro bullfrog gastric mucosa was examined using the inhibitors cycloheximide and puromycin. Both inhibitors reduced [3H]leucine incorporation by more than 90%. The inhibition of protein synthesis had no influence on spontaneous acid secretion nor did it effect secretory stimulation by histamine, carbachol, pentagastrin, or theophylline. Oxygen consumption by nonstimulated and theophyllinestimulated tissues was shown to be independent of protein synthesis. The dramatic morphological changes observed in oxyntic cells during a transition from rest to active secretion persisted in cycloheximide-and puromycin-treated tissues. Stereological analysis of the apical membrane surface area density failed to demonstrate any quantitative influence of protein synthesis inhibition. These studies quantitatively confirm that protein synthesis is not required for the biochemical and morphological events involved in acid secretion by the in vitro frog gastric mucosa.