Metabolic changes associated with gastric stimulation

The oxidation of radioactively labeled substrates showed a preferential utilization of butyrate over glucose or pyruvate by the in vitro frog gastric mucosa. The preference for butyrate was maintained in theophylline-stimulated tissues, but dinitrophenol stimulation of respiration resulted in a shift toward glucose metabolism. These results are interpreted as showing that theophylline-stimulated respiration is not driven by increases in cellular ADP and therefore is not a response to increased energy utilization. The preferential utilization of butyrate was also observed in rabbit gastric tubules, indicating that it is not species-specific. Stimulation of respiration by butyrate was shown to correlate with butyrate oxidation. These results are consistent with, but do not prove, the hypothesis that specific substrates stimulate acid secretion and respiration via their metabolism. Experiments using amytal and menadione showed that ATP and phosphocreatine are not sufficient energy sources for gastric secretion, and a specific amytal-sensitive reaction is postulated. This specific reaction and the substrates which supply it are seen to serve as rate-limiting reactions for acid secretion.