['The antioxidant action of diphenyl diselenide ((PhSe)(2)) is attributed to the mechanism by which (PhSe)(2) has pharmacological activity. Although (PhSe)(2) has glutathione peroxidase mimetic activity, the exact mechanism involved in its antioxidant effect has not yet been completely elucidated. In the present study, mechanisms involved in the antioxidant property of (PhSe)(2) (1-50 microM) were investigated.', "Dehydroascorbate (DHA) reductase- and glutathione S-transferase (GST)-like activity, 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical-scavenging activity and the protection against the oxidation of Fe(2+) were evaluated.", '(PhSe)(2) at concentrations equal to, or greater than, 5 microM showed DHA reductase- and GST-like activity. (PhSe)(2) was not a scavenger of DPPH or ABTS radicals and did not protect against the oxidation of Fe(2+).'] Does diphenyl diselenide in its selenol form have dehydroascorbate reductase and glutathione S-transferase-like activity dependent on the glutathione content?