Fig. 2. The effect of N-acetylcysteine (NAC) on the stability of HIF-1 protein in RTG-2 cells under normal oxygen conditions. The cells were treated with 0, 0.1, 1 or 10 mM NAC for 30 minutes, then they were maintained at 21% oxygen in the absence (0) or the presence of NAC, and in the absence of NAC at 1% oxygen (H) for 2 hours. HIF-1 protein was detected using immunoprecipitation techniques with HIF-1 antibody produced against rainbow trout protein.