Requirement for GSH in recycling of ascorbic acid in endothelial cells

Authors
Citation
Jm. May et al., Requirement for GSH in recycling of ascorbic acid in endothelial cells, BIOCH PHARM, 62(7), 2001, pp. 873-881
Citations number
56
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Pharmacology & Toxicology
Journal title
BIOCHEMICAL PHARMACOLOGY
ISSN journal
0006-2952 → ACNP
Volume
62
Issue
7
Year of publication
2001
Pages
873 - 881
Database
ISI
SICI code
0006-2952(20011001)62:7<873:RFGIRO>2.0.ZU;2-2
Abstract
Ascorbic acid may be involved in the defense against oxidant stress in endo thelial cells. Such a role requires that the cells effectively recycle the vitamin from its oxidized forms. In this work, we studied the ability of cu ltured bovine aortic endothelial cells (BAECs) to take up and reduce dehydr oascorbic acid (DHA) to ascorbate, as well as the dependence of ascorbate r ecycling on intracellular GSH. BAECs took up and reduced DHA to ascorbate m uch more readily than they took up ascorbate. Although BAECs in culture did not contain ascorbate, ascorbate accumulated to concentrations of 2-3 mM i n BAECs following incubation with 400 muM DHA. Extracellular ferricyanide o xidized intracellular ascorbate, which was recycled by the cells. Reduction of DHA, either when added to the cells or when generated in response to fe rricyanide, caused significant decreases in intracellular GSH concentration s. Depletion of intracellular GSH with 1-chloro-2,4-dinitrobenzene, diethyl maleate, and diamide almost abolished the ability of the cells to reduce DH A to ascorbate. DHA reduction by thioredoxin reductase was evident in dialy zed cell extracts, but occurred at rates far lower than direct GSH reductio n of DHA. These results suggest that maximal rates of DHA reduction, and th us recycling of ascorbate from DHA, are dependent upon GSH in these cells. (C) 2001 Elsevier Science Inc. All rights reserved.