Metabolism of D-fructose

D-fructose the most readily water-soluble sugar. It does not crystallize from stored juices. Because of its hygroscopicity, it retains moisture in sugar-preserved food and intensifies its flavor and aroma. Metabolism of D-fructose delivers less energy than sucrose. This saccharide neither causes nor accelerates tooth cavities. It accelerates ethanol metabolism. 

In recent years, crystalline D-fructose has been produced and offered not only as an unusually sweet sugar but as a beneficial sweetening agent for people with certain ailments or, because of its claimed ease of metabolism, for athletes in whom it is said to provide quick energy. A review of the voluminous literature on the metabolism of D-fructose presents relatively clear information, and an attempt is made in this article to set forth a useful summary. 

In adipose tissue, as in other tissues, D-fructose is transported by a mechanism different from that of D-glucose,69 and by a system that is not insulin-dependent.69 Metabolism of D-fructose is rapid, and is accomplished with the participation of fructokinase62 and a nonspecific hexokinase.70,71 D-Fructose utilization effectively occurs in adipose tissue of diabetic animals and of animals with inherited intolerance to D-fructose.72... 

Use of D-fructose by muscle cells is still a matter of debate. The results of in vitro experiments indicate rapid, muscular uptake of D-fructose, with both incorporation into glycogen and oxidation to carbon dioxide. However, when D-glucose is added in increasing amounts to muscle-tissue slices, D-fructose utilization decreases. It follows that metabolism of D-fructose in muscle under normal circumstances is limited, owing to competitive inhibition by D-glucose.73... 

Spermatozoa in ejaculated, mammalian semen are unusual in their considerable reliance on the metabolism of D-fructose, the principal... 

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