Possible Interaction: Glucose and Ascorbate

“A tentative explanation of this phenomenon could be related to the observed depression of the uptake of glucose, since glucose and ascorbate are known to compete for the same transporter.”

“This study indicates that the metabolic switch between glucose‐lactate could be detectable in vivo and might be modulated by Asc.”

“Acute loading of the cells for 30-60 min with ascorbate before the permeability assay prevented the high glucose-induced increase in permeability and decreased basal permeability at 5mM glucose.”

“ Ascorbate seemed to exert its effects through its oxidized product, dehydroascorbate, as the effects was prevented in the presence of D-glucose (10 mM).”

“By using ascorbate as substrate in human granulocytes, an inhibition of the transport by glucose could be found as well, however, the transport did not show a simple saturation kinetic."”

“Loading the cells with ascorbate during culture decreased apoptosis, both at 5 and 25 mM glucose.”

“Increasing concentrations of glucose in the transport media also significantly inhibited ascorbate uptake, but no effect of glucose was seen when glucose internalization was blocked by phlorizin.”

“ Glucose is a strong inhibitor of ascorbate uptake with a Ki of 3.7 mM and a stoichiometry of 1:1.”

“The presence of glucose (5 m m ) with ascorbate shifted the endpoint to 90% HbO 2 /10% MetHb while lactate (2 m m ) plus pyruvate (0.1 m m ) had no effect.”

“When red cells containing 100% MetHb at zero time were used, analysis of the initial … of HbO 2 formation in the presence of various substrates showed synergistic interaction between ascorbate (10 m … ) and glucose , additive activity with ascorbate and lactate, and less than additive activity with glucose and lactate.”

“The hypothesis is based … following: (1) transport of ascorbate across cell membranes … impaired by glucose , but facilitated by insulin; (2) glucose utilization is significantly accelerated by sublethal concentrations of endotoxin; (3) endotoxin-… sensitivity of tissue is enhanced by ascorbic deficiency; and (4) ascorbic acid deficiency alters mucosal barrier function.”