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gamma-Glutamylcysteine synthetase and GSH increase in quinone-induced oxidative stress in BPAEC.
Am J Physiol. 1994 Oct; 267(4 Pt 1):L414-21.AJ

Abstract

Glutathione (GSH), an important physiological antioxidant, is synthesized de novo by the sequential reactions of gamma-glutamylcysteine synthetase (gamma GCS) and GSH synthetase. In the present studies, incubation with the quinones 2,3-dimethoxy-1,4-naphthoquinone (DMNQ) and menadione (MQ), which generate superoxide and hydrogen peroxide, was used to investigate GSH synthesis in bovine pulmonary artery endothelial cells under oxidative stress. MQ can also cause initial depletion of GSH through conjugation, whereas DMNQ cannot. during continuous exposure to DMNQ (5 or 10 microM), elevation of GSH by DMNQ started after 6 h, almost doubled after 24 h, and remained at this level to 48 h. The elevation of GSH by DMNQ was mostly in the reduced form, and the ratio of reduced to oxidized glutathione remained unchanged for the first 24 h. Treatment with MQ (25 or 50 microM) for 30 min caused a significant decrease in GSH and total glutathione. After changing the medium to remove any residual MQ, GSH content doubled during the next 12 h. The enzymatic activity of gamma GCS, the rate-limiting enzyme of GSH biosynthesis, increased twofold after 12 h of exposure of cells to either 5 microM DMNQ or 50 microM MQ. Both DMNQ and MQ treatment caused concentration- and time-dependent increases in gamma GCS-mRNA expression. The elevation of gamma GCS-mRNA content by DMNQ for 12 h was completely blocked by coincubation with 0.05 microgram/ml actinomycin D but not 0.5 microgram/ml cycloheximide, suggesting the elevation of gamma GCS-mRNA content occurred through increased transcription. Our results suggest that increased de novo GSH synthesis, mediated by an elevation in gamma GCS, constitutes an adaptive response to oxidative stress.

Authors+Show Affiliations

Institute for Toxicology, University of Southern California, Los Angeles 90033.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

7943345

Citation

Shi, M M., et al. "Gamma-Glutamylcysteine Synthetase and GSH Increase in Quinone-induced Oxidative Stress in BPAEC." The American Journal of Physiology, vol. 267, no. 4 Pt 1, 1994, pp. L414-21.
Shi MM, Iwamoto T, Forman HJ. Gamma-Glutamylcysteine synthetase and GSH increase in quinone-induced oxidative stress in BPAEC. Am J Physiol. 1994;267(4 Pt 1):L414-21.
Shi, M. M., Iwamoto, T., & Forman, H. J. (1994). Gamma-Glutamylcysteine synthetase and GSH increase in quinone-induced oxidative stress in BPAEC. The American Journal of Physiology, 267(4 Pt 1), L414-21.
Shi MM, Iwamoto T, Forman HJ. Gamma-Glutamylcysteine Synthetase and GSH Increase in Quinone-induced Oxidative Stress in BPAEC. Am J Physiol. 1994;267(4 Pt 1):L414-21. PubMed PMID: 7943345.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - gamma-Glutamylcysteine synthetase and GSH increase in quinone-induced oxidative stress in BPAEC. AU - Shi,M M, AU - Iwamoto,T, AU - Forman,H J, PY - 1994/10/1/pubmed PY - 1994/10/1/medline PY - 1994/10/1/entrez SP - L414 EP - 21 JF - The American journal of physiology JO - Am. J. Physiol. VL - 267 IS - 4 Pt 1 N2 - Glutathione (GSH), an important physiological antioxidant, is synthesized de novo by the sequential reactions of gamma-glutamylcysteine synthetase (gamma GCS) and GSH synthetase. In the present studies, incubation with the quinones 2,3-dimethoxy-1,4-naphthoquinone (DMNQ) and menadione (MQ), which generate superoxide and hydrogen peroxide, was used to investigate GSH synthesis in bovine pulmonary artery endothelial cells under oxidative stress. MQ can also cause initial depletion of GSH through conjugation, whereas DMNQ cannot. during continuous exposure to DMNQ (5 or 10 microM), elevation of GSH by DMNQ started after 6 h, almost doubled after 24 h, and remained at this level to 48 h. The elevation of GSH by DMNQ was mostly in the reduced form, and the ratio of reduced to oxidized glutathione remained unchanged for the first 24 h. Treatment with MQ (25 or 50 microM) for 30 min caused a significant decrease in GSH and total glutathione. After changing the medium to remove any residual MQ, GSH content doubled during the next 12 h. The enzymatic activity of gamma GCS, the rate-limiting enzyme of GSH biosynthesis, increased twofold after 12 h of exposure of cells to either 5 microM DMNQ or 50 microM MQ. Both DMNQ and MQ treatment caused concentration- and time-dependent increases in gamma GCS-mRNA expression. The elevation of gamma GCS-mRNA content by DMNQ for 12 h was completely blocked by coincubation with 0.05 microgram/ml actinomycin D but not 0.5 microgram/ml cycloheximide, suggesting the elevation of gamma GCS-mRNA content occurred through increased transcription. Our results suggest that increased de novo GSH synthesis, mediated by an elevation in gamma GCS, constitutes an adaptive response to oxidative stress. SN - 0002-9513 UR - https://www.unboundmedicine.com/medline/citation/7943345/gamma_Glutamylcysteine_synthetase_and_GSH_increase_in_quinone_induced_oxidative_stress_in_BPAEC_ L2 - http://journals.physiology.org/doi/full/10.1152/ajplung.1994.267.4.L414?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -