Glucose Transport During Cell Cycle in IM9 Lymphocytes

Summary

Hexose uptake of the transformed lymphocyte cell line IM9 was analysed with respect to kinetics, responsiveness to insulin and insulin-like growth factor I and to cell cycle dependency. We found a K_m of 0.76 mM and a Vmax of 14.9 nMol/min/mg protein for 2-deoxy-D-[³H]glucose uptake. This K_m is in accordance with the values described for the erythrocyte type and the brain type glucose transporter. Hexose uptake of IM9 lymphocytes was not altered by physiological concentrations of insulin or IGF I. We investigated the 2-deoxy-D-[³H]glucose transport in cells, enriched in the different cell cycle phases by counterflow elutriation. The results were calculated for hypothetical pure fractions. Hexose uptake per cell is more than doubled during the S-phase and returns in G₂-cells to the basal value of G₁-phase.

Key words

Glucose Transport - Cell Cycle - IM9 Lymphocytes - Insulin - Insulin-Like Growth Factor I