|
|
||||||||
AJP - Lung Cellular and Molecular Physiology, Vol 262, Issue 5 637-L643, Copyright © 1992 by American Physiological Society
ARTICLES |
M. Chang, M. Shi and H. J. Forman
Cell Biology Group, Childrens Hospital, Los Angeles, California 90027.
Administration of menadione (vitamin K3; 2-methyl-1,4-naphthoquinone) to cultured bovine pulmonary artery endothelial cells caused a dose- and time-dependent depletion of cellular ATP and depletion of intracellular glutathione (GSH). The toxicity of menadione was correlated with an increase of menadione-glutathione conjugate in the medium and with an increase in H2O2 generation. Recent studies have suggested that GSH may be useful as a pharmacological agent to prevent oxidant injury. In the present study, treatment with exogenous GSH prevented the loss of cellular GSH and ATP caused by menadione. Protection by extracellular GSH involved two mechanisms. In one mechanism, extracellular GSH was degraded by gamma-glutamyl transpeptidase, producing substrates for subsequent intracellular de novo GSH synthesis. We found that the protective effect of extracellular GSH was decreased by inhibiting gamma-glutamyl transpeptidase. In the other mechanism, GSH reacted in the medium with menadione to form a conjugate. Although formation of the menadione-glutathione conjugate within cells may contribute to menadione toxicity, addition of menadione-glutathione conjugate to the medium was found to be nontoxic to endothelial cells. Thus exogenous GSH protected endothelial cells by two mechanisms: maintenance of intracellular GSH and prevention of menadione entrance into cells.
This article has been cited by other articles:
![]() |
X. Zhao, J. S. Alexander, S. Zhang, Y. Zhu, N. J. Sieber, T. Y. Aw, and D. L. Carden Redox regulation of endothelial barrier integrity Am J Physiol Lung Cell Mol Physiol, October 1, 2001; 281(4): L879 - L886. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. R. Simon, U. Rai, B. L. Fanburg, and B. H. Cochran Activation of the JAK-STAT pathway by reactive oxygen species Am J Physiol Cell Physiol, December 1, 1998; 275(6): C1640 - C1652. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. Wang and N. Ballatori Endogenous Glutathione Conjugates: Occurrence and Biological Functions Pharmacol. Rev., September 1, 1998; 50(3): 335 - 356. [Abstract] [Full Text] [PDF] |
||||
![]() |
R.-M. Liu, M. M. Shi, C. Giulivi, and H. J. Forman Quinones increase gamma -glutamyl transpeptidase expression by multiple mechanisms in rat lung epithelial cells Am J Physiol Lung Cell Mol Physiol, March 1, 1998; 274(3): L330 - L336. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. D. Potdar, K. L. Andrews, P. Nettesheim, and L. E. Ostrowski Expression and regulation of gamma -glutamyl transpeptidase-related enzyme in tracheal cells Am J Physiol Lung Cell Mol Physiol, November 1, 1997; 273(5): L1082 - L1089. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |