Fig. 7. A pre-treatment of cells with the antioxidant N-propylgallate (nPG) for 30 minutes increased the level of HIF-1 protein. A higher molecular weight component of HIF-1 protein appeared after a 2-hour treatment at 21% oxygen with the commonly used phosphorylating agents phorbol myristate acetate (PMA; 50 nM) or sodium vanadate (NaVO₃; 50 µM). The HIF-1 protein was detected using immunoprecipitation techniques with trout-specific HIF-1 antibody.