Interrelationships between the absorptions of glucose, sodium and water by the normal human jejunum.

Normal subjects were used to study the absorption of sodium and water from a wide range of glucose concentrations using the double-lumen tube perfusion technique (diagram published). 16 adults were perfused with various glucose concentrations from isotonic solutions in the upper jejunum. When isotonic saline was perfused little or no sodium or water absorption occurred; however when glucose was perfused in concentrations greater than 14 mM a significant stimulant effect was found. Glucose-saline mixtures of 56-84 mM gave maximum rates of absorption. Higher glucose concentration rates greatly modified the effects of glucose due to low luminal sodium concentrations. Studies comparing absorption in the upper jejunum of 5% maltose and 5% glucose suggested that contrary to usual procedure water absorption may not always be coupled to that of total solute in isoosmotic proportions. Although it is concluded that glucose probably primarily stimulates sodium absorption and that water absorption is passive the other possibilites that primary water absorption and solvent drag of sodium are involved in soute transport are discussed.