The effect of amino acids on the intestinal transport of L‐ and D‐xylose in vitro

1. The intestinal transport of D ‐xylose by sacs of everted small intestine of the hamster is partially inhibited by L ‐histidine in concentrations of 5, 10 and 20 m M but not of 2 m M . 2. 20 m M concentrations of D ‐histidine and L ‐methionine also produce inhibition. 3. The inhibition is not due to an alteration in water transport or to a change in pH of the incubating medium. 4. The rate of the intestinal transport of L ‐xylose is about ¼ of the rate of D ‐xylose transport and is unaffected by a 20 m M concentration of L ‐histidine.