RT-PCR analysis of HIF-1α and GLUT1 mRNA expression in SW480 and SW620 cell lines under normoxia and hypoxia conditions. Results of RT-PCR analysis of HIF-1α mRNA and GLUT1 mRNA expression in SW480 and SW620 cell lines incubated for approximately 24 and 48 h in hypoxia and normoxia conditions. The relative expression ratio of HIF-1α mRNA and GLUT1 mRNA under hypoxia conditions were all higher than normoxia in both cell lines. The mRNA levels of the housekeeping gene β-actin served as the internal control for the normalization of mRNA levels in experimental samples. The measured values in a series were normalized to the β-actin signal of the respective control.