The interactions of mesna and dimesna with the sulfate exchange in human red blood cells.

The influence of disodium 2-mercaptoethane sulfonate disulfide (mesna, Uromitexan) and sodium 2-mercaptoethane sulfonate (dimesna) on the carrier mediated exchange of 35S-sulfate in human red blood cells was investigated in vitro in order to contribute to the understanding of pharmakokinetics and organospecific action of mesna. Countertransport indicated uptake of mesna in washed red blood cells by the carrier. In contrast, dimesna inhibited the transport of sulfate in a competitive manner. However, when 35S-sulfate uptake into red cells was studied with whole blood, addition of mesna was found to be inhibitory, which was caused by its rapid conversion to dimesna by plasma components. It is concluded that conversion of the anion carrier substrate mesna into the inhibitor dimesna is the reason that mesna or dimesna cannot be detected in red blood cells in vivo.