SELECTIVE UPTAKE OF SELENITE BY RED-BLOOD-CELLS

Both organic and inorganic forms of selenium (Se) can be utilized in t he body, and the biotransformation of selenite into an organic form of Se in the bloodstream is the first step for the utilization of inorga nic Se, Selenite injected intravenously into rats was shown to be take n up rapidly and selectively by red blood cells (RBCs) through the ani on-exchange carrier, The uptake of selenite by RBCs was inhibited by 4 ,4'-diisothiocyano-2,2'-stilbene disulfonate, a specific inhibitor of the anion-exchange carrier (band 3 protein), The uptake was also inhib ited by chromate owing to the glutathione deprivation in RBCs, which w as confirmed by the inhibition by azodicarboxylic acid bis(dimethylami de). The presence of hydrogencarbonate in the incubation solution slig htly retarded the uptake of selenite by RBCs, Although Se effluxed int o the plasma was bound selectively to albumin, plasma proteins (albumi n) did not accelerate the uptake process, Based on these results, the rapid and selective uptake of selenite by RBCs was explained by the se lective and efficient uptake through the anion-exchange carrier, follo wed by reduction by glutathione.