Endothelial cell cystine uptake and glutathione increase with N,N-bis(2- chloroethyl)-N-nitrosourea exposure

S. M. Deneke, R. A. Lawrence, S. G. Jenkinson

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Glutathione (γ-glutamylcysteinylglycine, GSH) is an important cellular antioxidant. In typical cultured cell preparations GSH synthesis is limited by the availability of intracellular cysteine. Because extracellular cystine is the chief source of intracellular cysteine in cultured cells, increasing cystine transport can result in increased intracellular GSH. Depletion of GSH or exposure to oxidants has been shown to stimulate cystine transport in bovine pulmonary endothelial cells and other cell types. BCNU [N,N-bis(2- chloroethyl)-N-nitrosourea] is a potent inhibitor of glutathione reductase (GSSG-Red). We examined the effects of BCNU on cystine uptake by bovine pulmonary artery endothelial cells (BPAEC). We hypothesized that blocking GSSG-Red could result in increased cellular uptake of cystine to replenish decreases in GSH caused by oxidation. Levels of BCNU between 0.005 and 0.05 mM added to the cell culture medium inhibited GSSG-Red at 2, 4, and 24 h after addition. BCNU treatment resulted in concentration-dependent increases in both cystine uptake and GSH levels after 24 h of exposure. The increases in uptake were specific for cystine and glutamate and were sodium independent, suggesting induction of a x(c)/--like transport system. No intracellular accumulation of GSSG was measured nor was any significant depletion of GSH noted at any time of BCNU exposure.

Original languageEnglish (US)
Pages (from-to)L301-L304
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume262
Issue number3 6-3
DOIs
StatePublished - 1992
Externally publishedYes

Keywords

  • amino acid transport
  • antioxidants
  • glutathione reductase
  • pulmonary endothelium

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology

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