Effect of Phosphates and the pH on Sugar Absorption

Abstract

THERE has been little discussion on the work of Magee and Reid¹ showing that the addition of phosphates at pH 7 to the liquid to be absorbed activates intestinal absorption of glucose but not that of xylose^2–5. Laszt³ attributes such an effect to the buffer action of the phosphates, as with other buffers at pH 7 he obtained analogous increases; between pH 4 and 8 he found an optimum of absorption at pH 7. Gellhorn and Moldavsky⁶, however, arrived at opposite conclusions; in their opinion absorption would be much greater if instead of maintaining the pH at 7, it is somewhat displaced towards the acid or alkaline side. Difficulties in the interpretation of other results have induced us to return to these problems.