Glutathione ester delays the onset of scurvy in ascorbate-deficient guinea pigs
Autor: | Jihong Han, Johannes Martensson, Owen W. Griffith, Alton Meister |
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Rok vydání: | 1993 |
Předmět: |
Vitamin
Male medicine.medical_specialty Antioxidant medicine.medical_treatment Guinea Pigs Mitochondria Liver Ascorbic Acid Biology Kidney Guinea pig chemistry.chemical_compound Internal medicine medicine Animals Lung Multidisciplinary Kidney metabolism Brain Glutathione Metabolism Ascorbic acid Mitochondria Endocrinology chemistry Liver Toxicity Ascorbic Acid Deficiency Scurvy Research Article |
Zdroj: | Proceedings of the National Academy of Sciences of the United States of America. 90(1) |
ISSN: | 0027-8424 |
Popis: | Previous studies showed that administration of ascorbate to glutathione (GSH)-deficient newborn rats and guinea pigs prevented toxicity and mortality and led to increased tissue and mitochondrial GSH levels; ascorbate thus spares GSH. In the present work, we tried to answer the converse question: Does administration of GSH spare ascorbate? Because administered GSH is not well transported into most cells, we gave GSH monoethyl ester (which is readily transported and converted into GSH intracellularly) to guinea pigs fed an ascorbate-deficient diet. We found that treatment with GSH ester significantly delays appearance of the signs of scurvy and that this treatment spares ascorbate; thus, the decrease of tissue levels of ascorbate was delayed. The findings support the conclusions that (i) GSH is essential for the physiological function of ascorbate because it is required in vivo for reduction of dehydroascorbate and (ii) there is metabolic redundancy and overlap of the functions of these antioxidants. The sparing effect of GSH in scurvy may be mediated through an increase in the reduction of dehydroascorbate (which would otherwise be degraded) and to antioxidant effects of GSH that are also produced by ascorbate. Other studies indicate that GSH deficiency in adult mice stimulates ascorbate synthesis in liver. During this work we found that administration of GSH itself is highly toxic to ascorbate-deficient guinea pigs when given in divided i.p. doses totaling 3.75 mmol/kg daily. |
Databáze: | OpenAIRE |
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