Figure 5

Quantitation of the cell culture medium pH. The media from cell cultures were collected after transfection of the cells with HIF-1α siRNA vector or a HIF-1α expression plasmid and exposure to hypoxic conditions for 24 h. The pH of the cell culture medium measured immediately after samples collected (n = 5 in each group). $, P < 0.05 compared to normoxic mock and HIF-1α siRNA transfected; *, P < 0.05 compared to hypoxic HIF-1α siRNA and HIF-1α expression plasmid with HEPES; #, P < 0.05 compared to hypoxic HIF-1αexpression plasmid with or without 2-DG. siRNA: HIF-1α siRNA EGFP-pSUPER vector transfected, Mock: mock-transfected, HIF: HIF-1α expression plasmid transfected, HIF+2-DG: Cells were transfected with HIF-1α expression plasmid and cultured with 2-DG, HIF+HEPES: Cells were transfected with HIF-1α expression plasmid and cultured with medium containing HEPES.