Relationship of mitochondrial membrane potential to hemoglobin synthesis during Friend cell maturation.

Previous studies have shown that exposure to imidazole dissociates hemoglobin synthesis from other aspects of cell maturation in dimethylsulfoxide (DMSO)-treated mouse erythroleukemia (MEL) cells. In the present study, we have found that imidazole causes hyperpolarization of the mitochondrial membrane in MEL cells exposed to DMSO, in contrast to the depolarization observed with DMSO alone. Like the defect in hemoglobin synthesis, membrane hyperpolarization is reversible upon removal of imidazole and incubation of cells with DMSO alone. These correlations suggest that alterations in the electrostatic properties of the mitochondrial membrane, due directly or indirectly to the effects of imidazole, interfere with heme synthesis but not with other aspects of the maturation process in these developing erythroid cells.