Preferential transport of glutathione versus glutathione disulfide in rat liver microsomal vesicles

A bi directional, saturable transport of glutathione (GSH) was found in rat liver microsomal vesicles. GSH transport could be inhibited by the anion t ransport blockers flufenamic acid and 4,4'-diisothiocyanostilbene-2,2'-disu lfonic acid. A part of GSH taken up by the vesicles was metabolized to glut athione disulfide (GSSG) in the lumen. Microsomal membrane was virtually no npermeable toward GSSG; accordingly, GSSG generated in the microsomal lumen could hardly exit. Therefore, GSH transport, contrary to previous assumpti ons, is preferred in the endoplasmic reticulum, and GSSG entrapped and accu mulated in the lumen creates the oxidized state of its redox buffer.