Figure 4: 10% hypoxia administered for 0, 3, 4, 6, 7, 9, 12 hours results in stimulation of erythropoietin (EPO) mRNA in rat kidney cortex. mRNA levels were quantified by qRT-PCR result fold change normalized by 18s rRNA housekeeping gene, (N=4). *Values significantly different compared with the control group (* P < 0.05, ** P < 0.01, *** P < 0.001).