tert-Butyl hydroperoxide-induced lipid signaling in hepatocytes: involvement of glutathione and free radicals

Citation
C. Martin et al., tert-Butyl hydroperoxide-induced lipid signaling in hepatocytes: involvement of glutathione and free radicals, BIOCH PHARM, 62(6), 2001, pp. 705-712
Citations number
37
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Pharmacology & Toxicology
Journal title
BIOCHEMICAL PHARMACOLOGY
ISSN journal
0006-2952 → ACNP
Volume
62
Issue
6
Year of publication
2001
Pages
705 - 712
Database
ISI
SICI code
0006-2952(20010915)62:6<705:THLSIH>2.0.ZU;2-8
Abstract
tert-Butyl hydroperoxide (TBHP) mobilizes arachidonic acid (AA) from membra ne phospholipids in rat hepatocytes under cytotoxic conditions, thus leadin g to an increase in intracellular AA, which precedes cell death. In the pre sent work, the involvement of lipid peroxidation, thiol status, and reactiv e oxygen species (ROS) in the intracellular AA accumulation induced by 0.5 MM TBHP was studied in rat hepatocytes. Cells treated with TBHP maintained viability and energy status at 10 min. However, TBHP depleted GSH, as well as inducing lipid peroxidation and ROS formation, detected by dichlorofluor escein (DCF) fluorescence. TBHP also significantly increased (32.5%) the in tracellular [C-14]-AA from [C-14]-AA-labelled hepatocytes. The phospholipas e A(2) (PLA(2)) inhibitor, mepacrine, completely inhibited the [C-14]-AA re sponse. The addition of antioxidants to the cell suspensions affected the T BHP-induced lipid response differently. The [C-14]-AA accumulation correlat ed directly with ROS and negatively with endogenous GSH. No correlation bet ween [C-14] -AA and lipid peroxidation was found. Promethazine prevented li pid peroxidation and did not affect the [C-14]-AA increase. We conclude tha t TBHP stimulates the release of [C-14]-AA from membrane phospholipids thro ugh a PLA(2)-mediated mechanism. Endogenous GSH and ROS play a major role i n this effect, while lipid peroxidation-related events are unlikely to be i nvolved. Results suggest that specific ROS generated in iron-dependent reac tions, different from lipid peroxyl radicals, are involved in PLA(2) activa tion, this process being important in TBHP-induced hepatocyte injury. (C) 2 001 Elsevier Science Inc. All rights reserved.