GSH / GSSG ratio measurement under normoxia and two different terms of hypoxia. 2 × 105/ml cells in 0.02 ml RPMI1640 + 3% FCS were cultured under normoxia (21% O2) or hypoxia (1% O2) (short term hypoxia) for 24 hours in triplicate. Then, GSH / GSSG ratio was measured by using GSH / GSSG-Glo Assay. After 7 days culture under hypoxia with two medium changes, GSH / GSSG ratio was also measured by using these cells cultured for 24 more hours under hypoxia (long term hypoxia). GSH / GSSG ratio of NB4 under normoxia was 3.02 ± 0.067 and that under short term hypoxia was 2.31 ± 0.020 (p = 0.0005). GSH / GSSG ratio under long term hypoxia (2.69 ± 0.028) was significantly higher than that of short term hypoxia (p = 0.0004). GSH / GSSG ratio of THP-1 under normoxia (1.50 ± 0.094) and hypoxia (1.50 ± 0.083) was almost equal. THP-1 under longer hypoxia showed increase of GSH / GSSG ratio (2.09 ± 0.077) compared with that under short term hypoxia (p = 0.0065). SH: under short term hypoxia, LH under long term hypoxia, N: under normoxia. *** p < 0.001, ** p < 0.01, * p < 0.05, ns p > 0.05 (unpaired, two-tailed t-test).