Changes in the intracellular reduced/oxidized glutathione ratio (GSH/GSSG) are crucial reduction-oxidation (redox) events that trigger downstream proliferation or death responses. We investigated the molecular mechanisms underlying redox-mediated cell signaling upon an oxidative insult by treating U937 cells with exogenous nonpermeable GSSG. This treatment results in a significant decrease of e...

Redox cycling metabolism of diquat catalyzes generation of reactive oxygen species, and diquat-induced acute hepatic necrosis in male Fischer 344 (F344) rats has been studied as a model of oxidant mechanisms of cell killing in vivo. At equal doses of diquat, female F344 rats sustained less hepatic damage than did male rats, as estimated by plasma alanine aminotransferase (ALT) activities after ...

The epithelial cells on the alveolar surface of the human lower respiratory tract are vulnerable to toxic oxidants derived from inhaled pollutants or inflammatory cells. Although these lung cells have intracellular antioxidants, these defenses may be insufficient to protect the epithelial surface against oxidants present at the alveolar surface. This study demonstrates that the epithelial linin...

Two kinetically and thermodynamically distinct thiol/disulfide redox changes are observed during the reversible thioredoxin fb-catalyzed reduction and oxidation of spinach chloroplast fructose-1,6-bisphosphatase by dithiothreitol. The two processes, which occur at different rates and with different equilibrium constants, can be observed independently in either the reduction (activation) or oxid...

PURPOSE Glutathione is a tripeptide consisting of cysteine, glycine, and glutamate and functions as a major antioxidant. It is synthesized endogenously in humans. Glutathione protects thiol protein groups from oxidation and is involved in cellular detoxification for maintenance of the cell environment. Reduced glutathione (GSH) has a skin-whitening effect in humans through its tyrosinase inhibi...

A microtiter plate assay for quantitation of reduced (GSH) and oxidized (GSSG) glutathione in the rat liver tissue and bile is described. The assay is based on the established enzymatic recycling method and a new thiol-masking reagent, 1-methyl-4-vinyl-pyridinium trifluoromethane sulfonate (M4VP). Samples were first processed by homogenization with (liver) or addition of (bile) sulfosalicylic a...

Cadmium (Cd) is considered as one of the most toxic metals for plant growth and development. In the present study, we investigated the role of externally applied hydrogen peroxide (H2O2) in regulating the antioxidant defense and glyoxalase systems in conferring Cd-induced oxidative stress tolerance in rapeseed (Brassica napus L.). Seedlings were pretreated with 50 μM H2O2 for 24 h. These pretre...

The method for the estimation of oxidized and reduced glutathione (GSSG and GSH) based on the glyoxalase reaction (Woodward, 1935; Martin & Mcllwain, 1959) is the only method available with a high degree of specificity. The present paper suggests another specific method based on thioldisulphide exchange reactions. Pihl, Eldjarn & Bremer (1957) have shown that exchange reactions between GSH and ...

I T HAS BECOME increasingly apparent that many forms of hemolytic disease are due to hereditary enzyme deficiencies affecting the erythrocytes. The drug-induced hemolytic anemias may be due to glucose-fl-phosphate dehydrogenase (G-6-PD ) deficiency, glutathione reductase (GSSG-R) deficiency, or to a deficiency in reduced glutathione (GSFI ). Nonspherocytic congenital hemolytic anemia may be due...

PURPOSE To determine whether long-term cultured nondividing human retinal pigment epithelial (hRPE) cells are sensitive to oxidant-induced apoptosis and whether the Fas pathway is involved in the process. METHODS Confluent hRPE cells were maintained for 2 to 3 months in the basal medium (DMEM containing 2% fetal bovine serum) with one medium change per week. DNA synthesis was measured by inco...