Adenine and pyridine nucleotide levels as well as those of phosphate, phosphocreatine, lactate, pyruvate, beta-hydroxybutyrate, acetoacetate, glucose, and glycogen were measured in histologically defined parietal and mucous cell sections of biopsies of dog gastric mucosa at rest, and in various secretory states. As a result of stimulation of secretion, there appeared to be no change in adenine nucleotide levels, or phosphocreatine, but there was a rise in inorganic phosphate and a fall in phosphorylation potential. However, there was a marked increase in NADH, but no change in NADPH with onset of acid secretion. The increase in the lactate to pyruvate ratio showed that the increased NADH level occurred in the cytoplasm and these data are discussed with reference to change in cell pH.