FIG. 2.

During hypoxia, growth rate of wild-type cells, but not null cells, is dependent on glucose availability. Triplicate plates of cells were cultured in either high-glucose (4,500-mg/ml) (A) or low-glucose (1,000-mg/ml) (B) DMEM at normoxia (solid bars) or hypoxia (striped bars), and the cell count ± the SEM was determined at 72 h following trypsinization by using a hemacytometer. The loss of HIF-1α does not affect growth at normoxia under high- or low-glucose conditions. In addition, at hypoxia, the availability of glucose does not affect the growth rate of the null cells since the number of cells present is approximately the same whether cells are cultured in high- or low-glucose medium (compare panels A and B). However, during hypoxia there is a significant difference in cell density between wild-type cells and null cells cultured in high glucose due to the increased growth of wild-type cells in high-glucose medium (compare panels A and B).