HIF-1α mRNA expression in human GaMG glioblastoma cell line after in vitro application of different hypoxic conditions. For experimental settings refer to Fig. 2. Semiquantitative RT-PCR did not reveal any regulatory event under different oxygenation, hypoxia and reoxygenation conditions. Bar graphs show band intensities after densitometric evaluation and normalisation to β-actin expression as it is known from previous experiments. Representative experiment out of three.