Absorption of carbohydrate-electrolyte solutions in rat duodenojejunum

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Abstract
Commonly used oral electrolyte solutions are based on glucose, or sucrose, and 90 mM Na+. We had been disappointed with the ability of such solutions to improve Na+ absorption in patients with extensive resection of distal small bowel. Therefore, we tested the effect on net Na+ and water transport of combinations of different carbohydrates (glucose, sucrose, and glucose polymers) and NaCl in the rat duodenojejunum. Absorption was measured under steady-state conditions in unanesthetized animals which were infused with a different combination every hour for up to 5 hr. Of the various combinations, 10 mM glucose polymer (equivalent to 56 mmol of glucose as glucose oligosaccharides), or 60 mM glucose promoted net Na+ absorption from 120 mM NaCl and 20 mM KCl, but the glucose polymer infusate promoted more rapid water absorption than did the infusate containing glucose. The infusate of 10 mM glucose polymer in saline was initially hypotonic (276 mosmol/kg), but it became isotonic (298 mosmol/kg) as the glucose polymer was hydrolyzed during its passage through the duodenojejunum. In contrast, an infusate of 60 mM sucrose with 120 mM NaCl and 20 mM KCl remained hypertonic (320 mosmol/kg), and it did not promote water and Na+ absorption by the duodenojejunum. The efficacy of 10 mM glucose polymer with 120 mM NaCl should be tested in patients with short-bowel syndrome due to distal bowel resection.