Modulation of Liver l-γ-Glutamyl-l-cysteinylglycine Homeostasis By N-Acetyl-Glucosamine-thiazolidine-4(R)-carboxylic Acid in Mice

The properties of modulating liver l-γ-glutamyl-l-cysteinylglycine (GSH) homeostasis by thiazolidine derivative N-acetyl-glucosamine-thiazolidine-4(R)-carboxylic acid (GlcNAcCys) and the underlying mechanisms were investigated in l-buthionine-[S,R]-sulfoximine (BSO)-induced mice liver GSH depletion model. The data show that BSO (6 mmol/kg body weight; intraperitoneally) significantly decreased liver total sulfhydryl and GSH concentrations when compared with control. When mice were treated with different doses of GlcNAcCys (200, 400, 900 mg/kg body weight; intraperitoneally, respectively), total sulfhydryl and GSH concentrations were significantly increased when measured 6 hours after treatment. The activities of GSH-associated enzymes were also measured. Liver glutathione S-transferase (GST) activities were significantly decreased by BSO compared with the control, and GlcNAcCys significantly increased GST activity. Moreover, reverse-transcriptase polymerase chain reaction data indicated that GlcNAcCys could significantly induce glutamylcysteine ligase catalytic subunit c mRNA transcription. The mRNA levels of transcription factors c-jun and c-fos were increased by BSO administration but were decreased back to normal after the administration of GlcNAcCys. In a conclusion, GlcNAcCys can modulate liver GSH homeostasis, which may be related to its ability to induce glutamylcysteine ligase catalytic subunit transcription. GlcNAcCys has potential hepatoprotective properties by increasing GSH content, increasing GST activity.