Glucose and sorbose absorption at various levels of rat small intestine

Abstract

The passage of glucose and sorbose across the wall at various levels of rat small intestine has been studied in vitro. ‘Uphill’ glucose transport was demonstrated in the jejunum and upper half of the ileum but could not be seen in the terminal quarter of small intestine. Aerobically, in the mid-jejunum glucose absorption from the mucosal solution was about 5.5 times as rapid as in the terminal ileum; the aboral decline in absorptive activity, however, occurred only in the lower half of the small intestine; the upper half absorbed glucose at a nearly constant rate throughout. No aboral decline for rate of glucose transfer into the serosal solution was noticed in the upper three-quarters of small intestine, but in the lower quarter the drop was precipitous. The effects of hypoxia and fluoride poisoning, respectively, on glucose movements were much more severe in the upper than in the lower portions of small intestine. Fluoride (48 mm) completely abolished the absorptive activity gradient for glucose along the small intestine. Sorbose movements were quite similar in rate to the fluoride-inhibited glucose movements.