The effect of iron chelators [desferrioxamine (DFO) and pyridoxal isonicotinoyl hydrazone (PIH)], iron donors [ferric ammonium citrate (FAC) and heme], the heme precursor, protoporphyrin IX (PIX), and the heme synthesis inhibitor, succinylacetone (SA), on the protein levels of the transferrin receptor (TfR) in Friend 707 cells.

Friend cells were incubated in the presence (+) or absence (−) of 1.5% DMSO for 96 hours at 37°C. After this, the incubation was continued for a further 20 hours at 37°C in the presence (+) or absence (−) of 1.5% DMSO alone (controls) or in these media containing either DFO (100 μM), FAC (100 μg/mL), PIH (50 μM), hemin (50 μM), PIX (50 μM), or SA (2 mM). Western blot analysis was performed as described in “Materials and methods.” The result illustrated is typical of 5 experiments performed.