Krebs cycle, pentose phosphate pathway, and glycolysis in the uninvolved gastric mucosa of peptic ulcer and gastric cancer patients

Abstract

Uninvolved gastric mucosa from duodenal ulcer, gastric ulcer, and gastric cancer patients was incubated with [1-14C]glucose and [6-14C]glucose in order to assess the relative contributions of the pentose phosphate pathway and Krebs cycle to glucose metabolism. [14C]Glucose counts retained by the tissue, glycolysis, and pyruvate formation were also measured. Tumor tissue from the cancer patients was included in the study. Less than 1.2% of the glucose entering the tissues was metabolized via the pentose phosphate pathway; suggesting that this pathway plays a minor role in energy production from glucose. The major determinant of energy production was the Krebs cycle. Its contribution to glucose metabolism was greatest in the body mucosa of duodenal ulcer patients, less in the uninvolved body mucosa of gastric ulcer patients, and lower still in the corresponding body mucosa of gastric cancer patients. The low levels of Krebs cycle activity seen in the latter tissue resembled those of uninvolved antral mucosa. The smallest Krebs cycle contribution was seen in tumor tissue. [14C]Glucose counts retained by the tissue and glycolysis both tended to vary inversely with Krebs cycle activity among the tissues studied. Thus, both were small in the body mucosa of noncancer patients and somewhat larger in the body mucosa of cancer patients, in uninvolved antral mucosa and in tumor tissue.