D-Fructose in Adipose Tissue

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 

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