Glutathione GSH

The FAD-dependent enzyme glutathione reductase plays a role in the antioxidant system. Glutathione reductase restores reduced glutathione (GSH), the most important antioxidant in erythrocytes, from oxidized glutathione (GSSG) [1, 2]. 

Okada et al. examined the effects of TBT on cellular content of glutathione (GSH) in rat thymocites using a flow cytometer and 5-chloromethylfluorescein diacetate, a fluorescent probe for monitoring the change in the cellular content of GSH. TBT at nanomolar concentrations reduced the cellular content of GSH. There is an important implication on the TBT-induced depletion of cellular GSH since GSH has an important role in protecting the cells against oxidative stress and chemical and metal intoxications. TBT-induced decrease in cellular content of GSH in thymocytes may increase the vulnerability of the immune system. ° ... 

Activities of glutamate-pyruvate transaminase (SGPT, GPT) (EC 2.6.1.2), L-y -glutamyl-transferase (y-GT) (EC 2.3.2.2) and level of triglycerides (TG) in serum, as well as levels of glutathione (GSH) and malondialdehyde (MDA) in the liver were determined. 

The glutathione (GSH) level was assayed by the method of Sedlak and Lindsay (ref. 14), using Ellman s reagent (5,5-dithio-bis-(2-nitrobenzoic acid). Calibration was carried out parallely to each series, using reduced glutathione as a standard. 

Reduced glutathione (GSH) is important in the metabolism of the RBC, in part to counteract the action of potentially toxic peroxides the RBC can synthesize GSH and requires NADPH to return oxidized glutathione (G-S-S-G) to the reduced state. 

Glutathione (GSH) Liver Mice No Decreased Balthrop and Braddon (1985)... 

Figure 4.9 Effect of reduced glutathione (GSH) (0.25-1.0 ihm) and oxidized glutathione (GSSG) (0.25-1.0 mM) on ouabain-sensitive Na/K ATPase activity. An isolated Na/K ATPase preparation was prepared from fresh bovine ventricular tissue. Na/K ATPase activity was determined and quantified by the ouabain-sensitive hydrolysis of ATP to yield Inorganic phosphate. The rate of inorganic phosphate production was compared prior to and following the addition of either GSH or GSSG to the Incubation mixture. The data are presented as...

Figure 4.11 Effect of glutathione on the reduction of myocardial Na/K ATPase activity associated with Ischaemia and reperfuslon. Isolated rat hearts were perfused in the Langendorff mode with oxygenated Tyrode s solution for a control period of 10 min. This was immediately followed by a 60 min period of global, stop-flow ischaemia and 5 min subsequent reperfuslon. Glutathione (GSH) (1 mM) was added to the perfusion fluid 5 min prior to the onset of Ischaemia and throughout the reperfuslon period. The data are presented as means standard errors of the means (n = 6).

Hydroxydopamine (6-OHDA) is a neurotoxin that destroys catecholaminergic neurons in the brain. This toxicity is believed to be related to the production of ROS by the neurotoxin. Rats were fed chronically with vitamin E and then challenged with 6-OHDA. The usual depletion of SOD and reduced glutathione (GSH) in most brain regions was attenuated by the vitamin E pretreatment. The authors attributed this success to scavenging by the augmented brain levels of vitamin E (Perumal et al., 1992). 

Glutathione reductase (GR) catalyzes the reduction of oxidized glutathione (GSSG) to reduced glutathione (GSH) using NADPH provided from the hexose monophosphate pathway. GR, a ubiquitous flavoenzyme, maintains a high value of two for the GSH/GSSG ratio in the red blood cells. l,3-Bis(2-chloroethyl)-nitrosourea (BCNU) selectively inhibits cellular GR. GR is composed of two identical subunits, each of molecular mass 50 kDa (S8). The three-dimensional structure and mechanism of catalysis have been established for human GR (K17). 

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