Stress and Dietary Influence on the Direct Oxidative Pathway of Carbohydrate Metabolism in the Intestine By

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Abstract
The activity of a major carbohydrate metabolic pathway, the hexosemonophosphate shunt, has been investigated in the jejunal mucosa of 146 rats by assay of mucosal homogenates for activity of glucose-6-phosphate dehydrogenase and 6-phospho-gluconate dehydrogenase. Normal animals, animals subjected to a variety of environmental stresses (restraint, pylorus-ligation, starvation, and corticoid injection), and animals subjected to refeeding treatments following starvation were studied. Glucose-6-phosphatc dehydrogenase was more responsive to environmental stress and refeeding than 6-phosphogluconate dehydrogenase, but directional changes for both enzymes were similar. It was observed that starvation (48 hr), starvation (42 hr) plus pylorus-ligation (17 hr), starvation (42 hr) plus restraint (18 hr), and hydrocortisone 40 mg, im) induced significant depression of hexosemonophosphate shunt activity. Refeeding of NaCl (0.9 % per os) did not alter starvation-induced depression of the enzyme activities. However, refeeding of glucose (3 g, per os) and especially refeeding of a complete diet (Purina Laboratory Chow) significantly increased the starvation-induced hexosemonophosphate shunt depression over control (fed animals) values. Typical forestomach lesions and gastric content acidities were observed in pylorus-ligated rats, and typical lesions in the glandular stomachs of restrained rats were observed. It is concluded that the metabolism of glucose in the jejunal mucosa is highly responsive to both environmentally-induced stress and refeeding regimens, and it is suggested that metabolic alterations in carbohydrate metabolism of the gut mucosa may play some role, as yet unestabiished in the early pathogenesis of mucosal lesions.