Dec 1, 1969

Glucose uptake by isolated particles from rat epididymal tissue cells

Proceedings of the National Academy of Sciences of the United States of America
J R Carter, D B Martin

Abstract

A MICROSOMAL FRACTION FROM ISOLATED ADIPOSE TISSUE CELLS HAS BEEN PREPARED WHICH POSSESSES MANY FEATURES INDICATING THE PRESENCE OF A FUNCTIONAL GLUCOSE TRANSPORT SYSTEM: (1) D-glucose is both taken up and released more rapidly than L-glucose at all temperatures, but at 42 degrees L-glucose uptake reaches the level of D-glucose after prolonged incubation; (2) D-glucose uptake is inhibited by a specific inhibitor of glucose transport, phlorizin, while L-glucose uptake is unaffected; (3) Preincubation of the preparation at 42 degrees C has no effect on L-glucose uptake but partially inhibits D-glucose uptake; (4) Equilibrium uptake studies show a linear relationship between the final level of D-glucose taken up and D-glucose concentration in the medium; and (5) Preloading the membrane preparation with unlabeled D-glucose leads to a more rapid uptake of radioactive D-glucose. These findings are interpreted as showing the presence in the microsomal particles of a specific, bidirectionally functioning D-glucose transport system superimposed on uptake of both sugars by passive diffusion or "leaks." The retained D-glucose can be eluted from the membrane preparation and shown to be the unphosphorylated sugar.

  • References12
  • Citations9

References

Mentioned in this Paper

Molecular Stereochemistry
Phlorhizin
Fat Pad
Epididymis
Microsomes
Uptake
Glucose Import
Tritium
Anhydrous Dextrose
Glucose, (L)-Isomer

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