Kinetic properties of dehydroascorbic acid transport in erythrocytes of young and adult beagle dogs

Kinetic properties of dehydroascorbic acid (DHA) transport were studied in erythrocytes of beagle dogs at 1 and 12 months. DHA uptake was much faster in erythrocytes of dogs at 1 than 12 months. Young dogs showed much greater affinity for DHA than adult dogs and the rate of DHA uptake was not affected by glucose. It was due to the presence of fetal erythrocytes with high activity of Glut-1 glucose transporter in young dogs. In adult dogs, DHA uptake was slow and competitively inhibited by physiological concentrations of glucose. Glut-4 was identified as the carrier protein responsible for DHA uptake in erythrocytes of adult dogs. Glut-4 was hardly detectable in neonatal dogs, but increased to adult levels by 3 months as fetal erythrocytes were eliminated and switched to adult cells. © Springer-Verlag London Limited 2009.