The role of heme in the regulation of iron uptake during Friend cell differentiation.

The inhibitory effect of hemin on iron uptake and heme synthesis was investigated in Friend erythroleukemia cells. In cells of line 707 the inhibition of iron uptake became more pronounced after the induction of erythroid differentiation by dimethyl sulfoxide. No such rise in sensitivity to hemin was found in cells of line Fw, which are deficient in ferrochelatase activity and do not synthesize hemoglobin after induction of differentiation by sodium butyrate. The possibility that hemin influences mainly the uptake of iron used directly for heme synthesis, and to a lesser extent intracellular storage of iron is discussed.