The mechanism of uptake of ascorbic acid into osteoblasts and leukocytes

Ascorbic acid is taken up into osteoblast cells by a saturable, stereospecific, Na(+)-dependent transporter, accumulating ascorbic acid to a level 100-fold that in the medium. The ascorbic acid uptake rate correlated with intracellular hydroxyproline synthesis. A second, distinct mechanism has also been described for accumulation of ascorbic acid into neutrophils and myeloid leukemia cells. This appears to be Na(+)-independent and relies on the glucose transporter GLUT1 to ferry dehydroascorbic acid (DHA) into cells and then to trap it as ascorbic acid to a high concentration.