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Changes in gamma-glutamyltransferase activity in rat lung tissue, BAL, and type II cells after hyperoxia.
Am J Physiol. 1997 Sep; 273(3 Pt 1):L537-47.AJ

Abstract

The effect of hyperoxia on gamma-glutamyltransferase (gamma-GT), an important enzyme for the uptake of precursor molecules for intracellular synthesis of glutathione (GSH), has not been established. Our aim was to investigate the effects of prolonged subtoxic levels of hyperoxia on gamma-GT activity and GSH levels in lung tissue, epithelial lining fluid (ELF), and isolated rat type II cells immediately after their isolation and 48 h later when kept in culture in normoxia. Seventeen male Wistar rats were divided in three groups (n = 5-7) and were exposed to air or to 60 or 85% O2 for 7 days. Pulmonary gamma-GT activity increased in the 60 and 85% O2-exposed animals (1.6- and 3.2-fold, respectively), and tissue GSH levels increased only in the 60% O2 group (1.3-fold). In isolated type II cells from 60 and 85% O2-exposed animals, gamma-GT activity decreased by -70 and -88%, respectively, which was supported by cytochemical staining. Type II cell gamma-GT mRNA expression tended only to decrease after 85% O2. Type II cell gamma-GT activity strongly correlated with ELF gamma-GT (r = 0.60, P < 0.001), and ELF gamma-GT strongly correlated with ELF GSH (r = 0.75, P < 0.0001). When in culture, type II cell gamma-GT activity and GSH levels remained, respectively, 2.5- and 1.9-fold lower in the 60% O2-exposed group, but, in the 85% O2-exposed group, gamma-GT activity increased 2.1-fold, and GSH levels dropped to the levels of the control cells. Hyperoxia led to a concentration-dependent decrease in gamma-GT activity in rat type II cells, possibly by direct inactivation, but led to an increase in whole lung tissue gamma-GT. There seemed to be a negative feedback between intracellular GSH levels and type II cell gamma-GT activity. gamma-GT levels in the ELF were correlated with type II cell gamma-GT activity, but ELF gamma-GT did not seem to play an active role in the regulation of the ELF GSH pool. Hyperoxia decreased ELF GSH levels, possibly by increased degradation of GSH in the parenchymal lung tissue as a result of the increased gamma-GT activity.

Authors+Show Affiliations

Laboratory of Pneumology, Katholieke Universiteit Leuven, Belgium.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

9316487

Citation

Van Klaveren, R J., et al. "Changes in Gamma-glutamyltransferase Activity in Rat Lung Tissue, BAL, and Type II Cells After Hyperoxia." The American Journal of Physiology, vol. 273, no. 3 Pt 1, 1997, pp. L537-47.
Van Klaveren RJ, Dinsdale D, Pype JL, et al. Changes in gamma-glutamyltransferase activity in rat lung tissue, BAL, and type II cells after hyperoxia. Am J Physiol. 1997;273(3 Pt 1):L537-47.
Van Klaveren, R. J., Dinsdale, D., Pype, J. L., Demedts, M., & Nemery, B. (1997). Changes in gamma-glutamyltransferase activity in rat lung tissue, BAL, and type II cells after hyperoxia. The American Journal of Physiology, 273(3 Pt 1), L537-47.
Van Klaveren RJ, et al. Changes in Gamma-glutamyltransferase Activity in Rat Lung Tissue, BAL, and Type II Cells After Hyperoxia. Am J Physiol. 1997;273(3 Pt 1):L537-47. PubMed PMID: 9316487.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Changes in gamma-glutamyltransferase activity in rat lung tissue, BAL, and type II cells after hyperoxia. AU - Van Klaveren,R J, AU - Dinsdale,D, AU - Pype,J L, AU - Demedts,M, AU - Nemery,B, PY - 1997/10/8/pubmed PY - 1997/10/8/medline PY - 1997/10/8/entrez SP - L537 EP - 47 JF - The American journal of physiology JO - Am. J. Physiol. VL - 273 IS - 3 Pt 1 N2 - The effect of hyperoxia on gamma-glutamyltransferase (gamma-GT), an important enzyme for the uptake of precursor molecules for intracellular synthesis of glutathione (GSH), has not been established. Our aim was to investigate the effects of prolonged subtoxic levels of hyperoxia on gamma-GT activity and GSH levels in lung tissue, epithelial lining fluid (ELF), and isolated rat type II cells immediately after their isolation and 48 h later when kept in culture in normoxia. Seventeen male Wistar rats were divided in three groups (n = 5-7) and were exposed to air or to 60 or 85% O2 for 7 days. Pulmonary gamma-GT activity increased in the 60 and 85% O2-exposed animals (1.6- and 3.2-fold, respectively), and tissue GSH levels increased only in the 60% O2 group (1.3-fold). In isolated type II cells from 60 and 85% O2-exposed animals, gamma-GT activity decreased by -70 and -88%, respectively, which was supported by cytochemical staining. Type II cell gamma-GT mRNA expression tended only to decrease after 85% O2. Type II cell gamma-GT activity strongly correlated with ELF gamma-GT (r = 0.60, P < 0.001), and ELF gamma-GT strongly correlated with ELF GSH (r = 0.75, P < 0.0001). When in culture, type II cell gamma-GT activity and GSH levels remained, respectively, 2.5- and 1.9-fold lower in the 60% O2-exposed group, but, in the 85% O2-exposed group, gamma-GT activity increased 2.1-fold, and GSH levels dropped to the levels of the control cells. Hyperoxia led to a concentration-dependent decrease in gamma-GT activity in rat type II cells, possibly by direct inactivation, but led to an increase in whole lung tissue gamma-GT. There seemed to be a negative feedback between intracellular GSH levels and type II cell gamma-GT activity. gamma-GT levels in the ELF were correlated with type II cell gamma-GT activity, but ELF gamma-GT did not seem to play an active role in the regulation of the ELF GSH pool. Hyperoxia decreased ELF GSH levels, possibly by increased degradation of GSH in the parenchymal lung tissue as a result of the increased gamma-GT activity. SN - 0002-9513 UR - https://www.unboundmedicine.com/medline/citation/9316487/Changes_in_gamma_glutamyltransferase_activity_in_rat_lung_tissue_BAL_and_type_II_cells_after_hyperoxia_ L2 - http://journals.physiology.org/doi/full/10.1152/ajplung.1997.273.3.L537?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -