Effect of Bicarbonate on Sodium Absorption by the Human Jejunum

Abstract

THERE is much evidence to suggest that the absorption of sodium and water by the small intestine depends on concomitant absorption of non-electrolytes. Thus, in man, jejunal absorption from isotonic saline is very slow, but the rate of absorption of both sodium and water is greatly increased by the addition of glucose to the intestinal lumen^1,2. Galactose, but not fructose, has a similar effect on water absorption in man³. During the course of perfusion studies in man, we have found that bicarbonate ions have a stimulant effect on jejunal absorption of sodium and water and, furthermore, the magnitude of the effect on sodium is comparable with that of glucose.