The role of phosphorylation in glucose absorption from the intestine of the golden hamster.

The exact biochemical mechanism by which glucose is absorbed by the intestine against a concentration gradient is yet to be established. In 1933, Wilbrandt and Laszt (1) proposed the phosphorylation-dephosphorylation hypothesis for sugar absorption by the small intestine. In the same year Lundsgaard (2) suggested the same hypothesis for glucose reabsorption by the kidney tubules. Much of the evidence on which this hypothesis was originally based has since proved inadequate. On the other hand, conclusive evidence against the hypothesis is lacking. The present study was designed to test the hypothesis of the phosphorylation of glucose during the transport process. Ashmore et al. (3) employed a method for calculating the quantity of glucose which was phosphorylated to glucose B-phosphate by liver slices and subsequently hydrolyzed to glucose and inorganic phosphate. In a similar manner an attempt has been made in the present study to calculate the quantity of glucose arising from glucose 6-phosphate during the course of intestinal absorption of glucose by sacs of hamster intestine. The results obtained by such experiments indicate that only a small fraction of gluco,,e transported passes through glucose 6-phosphate as an intermediate.