Comparison of hepatoma and hepatocyte cells in response to hypoxia. (a) Survival ratio of hepatoma and hepatocytes cells in response to hypoxia. Hepatoma cell lines SMMC7721 and HepG2, and hepatocyte cell lines L02 and Chang were cultured under 2% O2 hypoxic condition for indicated times, and viable cells were assessed by live cell counting using trypan blue exclusion method. Data were expressed as relative to control values at normaxia incubated for the same period. (b) Glucose increases cell survival in response to hypoxia. Cells were pretreated with 5 mmol glucose and cultured under 2% O2 hypoxic condition for 24 h. (c) Glycolytic activity changes in response to hypoxia. Cells were cultured for 24 h under 2% O2. LDH activity, cellular lactate synthesis and glucose uptake were measured as described in materials and methods. LDH activity levels, cellular lactate production and glucose consumption are expressed relative to control values at normoxia. Control value is presented as 1. *, P < 0.05, difference between hepatoma cells and hepatocyte cells (a, c); **, P < 0.05, versus cells in the absence of glucose treatment (b). Results are means ± S.D. of four independent experiments.