Journal
FREE RADICAL BIOLOGY AND MEDICINE
Volume 28, Issue 3, Pages 381-389Publisher
ELSEVIER SCIENCE INC
DOI: 10.1016/S0891-5849(99)00251-8
Keywords
fatty acid hydroperoxide; prostaglandin; selenium; COX; LOX; bovine mammary endothelial cells; selenium-dependent glutathione peroxidase; free radicals
Funding
- NHLBI NIH HHS [R01HL60044] Funding Source: Medline
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Selenium (Se) is an integral part of the Se-dependent glutathione peroxidase (Se-GSH-Px) catalytic domain. By modulating the cellular levels of fatty acid hydroperoxides, Se-GSH-Px can influence key enzymes of arachidonic acid cascade, in this case cyclooxygenase (COX) and lipoxygenase (LOX). To investigate this phenomenon, the effects of cellular Se status on the enzymatic oxidation of arachidonic acid were investigated in bovine mammary endothelial cells (BMEC), which were cultured in either Se-deficient (-Se) or Se-adequate (+Se) media. When stimulated with calcium ionophore A23187, BMEC produced eicosanoids of both COX and LOX pathways. Compared with the Se-adequate cells, the production of prostaglandin I-2 (PGI(2)), prostaglandin F-2 (PGF(2 alpha)), and prostaglandin E-2 (PGE(2)) was significantly decreased in Se-deficient cells, whereas the production of thromboxane A(2) (TXA(2)) was markedly increased in the -Se BMEC cultures. Although the enzymatic oxidation of arachidonic acid by the LOX pathway was found to be relatively less than by the COX pathway, the BMEC cultured in -Se media produced significantly more 15-hydroperoxyeicosatetraenoic acid (15-HPETE) than the +Se cells produced. Based on these results, we postulate that cellular Se status plays an important regulatory role in the enzymatic oxidation of arachidonic acid by the COX and LOX pathways. The altered eicosanoid biosynthesis, especially the overproduction of 15-HPETE, in -Se BMEC may be one of the underlying biochemical phenomena responsible for vascular dysfunction during Se deficiency. (C) 2000 Elsevier Science Inc.
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