Rat Liver Glutathione: Possible Role as a Reservoir of Cysteine

Tateishi, Noriko; Higashi, Taneaki; Naruse, Akiko; Nakashima, Kenichi; Shiozaki, Hiroshi; Sakamoto, Yukiya

doi:10.1093/jn/107.1.51

Cited by 215 publications

(72 citation statements)

References 32 publications

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“…GSH is a non-toxic cysteine storage form with 10 -100 times higher concentrations in mammalian tissues than cysteine (17). Approximately one-third to one-half of the total liver GSH serves as a cysteine reservoir that can be released, when necessary (27).…”

Section: Gsh Functionsmentioning

confidence: 99%

Regulation of Neuronal Glutathione Synthesis

2008

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Abstract. The brain is among the major organs generating large amounts of reactive oxygen species and is especially susceptible to oxidative stress. Glutathione (GSH) plays critical roles as an antioxidant, enzyme cofactor, cysteine storage form, the major redox buffer, and a neuromodulator in the central nervous system. GSH deficiency has been implicated in neurodegenerative diseases. GSH is a tripeptide comprised of glutamate, cysteine, and glycine. Cysteine is the rate-limiting substrate for GSH synthesis within neurons. Most neuronal cysteine uptake is mediated by sodium-dependent excitatory amino acid transporter (EAAT) systems, known as excitatory amino acid carrier 1 (EAAC1). Previous studies demonstrated EAAT is vulnerable to oxidative stress, leading to impaired function. A recent study found EAAC1-deficient mice to have decreased brain GSH levels and increased susceptibility to oxidative stress. The function of EAAC1 is also regulated by glutamate transporter associated protein 3-18. This review focuses on the mechanisms underlying GSH synthesis, especially those related to neuronal cysteine transport via EAAC1, as well as on the importance of GSH functions against oxidative stress.

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Section: Gsh Functionsmentioning

confidence: 99%

Regulation of Neuronal Glutathione Synthesis

2008

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“…In the present study, we first investigated the impact of oral administration of L-cystine and L-theanine on the plasma cystine and glutamic acid concentrations. Then, changes in the hepatic GSH levels after antigenic stimulation were analyzed in mice given L-cystine and/or L-theanine orally, as the liver is known to contain high concentrations of GSH that decrease on stimulation with LPS [3,28]. The relative levels of interferon-γ (IFN-γ) and interleukin-10 (IL-10) are believed to be important in determining the balance between T helper (Th) 1/Th2 cells, which in turn determines the direction of activation of cell-mediated immunity or humoral immune response [16,23].…”

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confidence: 99%

Enhancement of Antigen-Specific Immunoglobulin G Production in Mice by Co-Administration of L-Cystine and L-Theanine

et al. 2007

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ABSTRACT. Supplementation with both cystine and glutamic acid increases the synthesis of glutathione (GSH), which has a marked effect on immune cell function, as compared with supplementation with either amino acid alone in human macrophages in vitro. As dietary glutamic acid is metabolized during intestinal transport, oral administration of L-theanine (γ-glutamylethylamide), which is metabolized to glutamic acid mainly in the liver, may act as a glutamic acid donor in vivo. The present study was performed to investigate the effects of oral administration of L-cystine and/or L-theanine on GSH levels and immune responses. Co-administration of L-cystine (200 mg/kg) and L-theanine (80 mg/kg) for 11 days before immunization significantly increased the levels of total GSH in the liver 6 hr after immunization as compared with the levels in control mice. To examine the effects of administration of L-cystine and/or L-theanine on the balance of T helper (Th) 1/Th2 cell responses, the serum ratios of the Th1 cytokine, interferon (IFN)-γ, and the Th2 cytokine, interleukin (IL)-10, were investigated. At 24 hr after immunization, co-administration significantly increased the IL-10/IFN-γ ratio compared with the ratios of the control and single-administration mice. Furthermore, co-administration before primary immunization significantly enhanced serum antigen-specific IgG levels. Taken together, these findings suggest that co-administration of L-cystine and L-theanine enhances antigen-specific IgG production partly through augmentation of GSH levels and Th2-mediated responses.

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“…It has been reported that the level of GSH decreases in vitamin C-deficient guinea pigs (13). The GSH level in an animal body is strongly dependent on food intake (14). In this experiment the actual amount of feed consumed by animals in group D gradually decreased.…”

Section: Discussionmentioning

confidence: 73%