DMO-transport in human red blood cells

The DMO (5,5-dimethyloxazolidine-2,4-dione) transport was studied in human red blood cells by measuring the¹⁴C-DMO back exchange under self exchange conditions from¹⁴C-DMO labeled cells at 0°C. The unidirectional DMO-flux was linearly related to the DMO concentration up to approx. 100 mM. The unidirectional DMO-flux increases as pH is reduced. The DMO transport is not inhibited by anion transport inhibitors like DIDS, SITS, dipyridamole, phlorhizin, salicylate or butanol. A close correlation between the unidirectional DMO-flux and DMOH, the unionized form of DMO, has been observed suggesting that DMO is transported predominantly by nonionic diffusion. The permeability of DMOH is 9.5·10^–6 cm/s (0°C) while the permeability of DMO^– cannot be assessed from our data.