Glucose metabolism in jejunal mucosa of fed, fasted, and streptozotocin-diabetic rats.

ANDERSON, JAMES Mr. Glucose metabolism in jejunal mucosa of fed, fasted, and streptototocin-diabetic rats. Am. J. Physiol. 226(l) : 226229. 1974.2Glycolytic and gluconeogenic enzyme activities and glycolytic rates were measured in the jejunal mucosa of rats. Tissue homogenates have high rates of glycolysis, which may make a significant contribution to the energy requirements of jejunal mucosa. In addition, jejunal mucosa has significant activities for several rate-limiting enzymes of gluconeogenesis with the activities of phosphoenolpyruvate carboxykinase, fructose diphosphatase, and glucose-6-phosphatase ranging from 12 to 21 yO of hepatic activities for these enzymes. Diabetes was associated with significant increases in hexokinase and glucose-6-phosphate dehydrogenase activities in jejunal mucosa; glucose utilization and lactate production per gram wet weight were also significantly increased. These increases in glycolytic rates may provide some of the energy required for the increased intestinal transport of carbohydrates and amino acids in diabetic animals. Fasting produced significant decreases in glycolytic enzyme activities and glycolytic rates, whereas the activities of three key gluconeogenic enzymes were significantly increased in jejunal mucosa. These observations suggest that fasting increases gluconeogenic rates in jejunal mucosa, whereas diabetes, which did not alter the activities of these three gluconeogenic enzymes, does not increase them.