Abstract
Recent investigations on the preparation of the pentose, xylose, have made this sugar, formerly one of the rare carbohydrates, available at a very moderate price. It has been suggested that xylose may be utilized in human nutrition as a “non-fattening sugar.” The renewed interest in xylose occasioned by its ready availability in pure form again raises the question of its rôle in nutrition. Although most of the literature would indicate that xylose ingestion does not lead to increased formation of liver glycogen, the question of its behavior in this respect is still an open one. We have accordingly studied the rate of absorption of xylose and the formation of glycogen from it in the young white rat.
The xylose was prepared from cottonseed hulls and was given to us by the Bureau of Standards and by Dr. J. L. Kassner of the University of Alabama, to whom we take this opportunity to express our indebtedness. The material as received was recrystallized from alcohol, dried at 40° in the oven and then in a desiccator for several weeks. The method of study was that of Cori as previously used in this laboratory for the study of the absorption of and glycogen formation from amino acids. 1
The results are presented in tabular form and require little comment. After the absorption of xylose over periods of 1, 2 and 3 hours, there was no significant change in glycogen content of the liver or the entire body (Groups 2, 3, 4) as compared with the control fasted animals (Group 1). Glucose administered in amounts comparable to xylose resulted in a marked deposition of glycogen after an absorption period of 3 hours (Group 5). Since, however, glucose was absorbed much more rapidly than was xylose, it seemed possible that glycogen formation might not result from the absorption of glucose in amounts comparable to the amount of xylose actually absorbed as shown by the experimental data.
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