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pubmed:abstractText |
Suspensions of rat peritoneal PMNLs elicited with glycogen were stimulated by calcium and an ionophore to produce leukotrienes from endogenous arachidonic acid. We investigated the effect of the non-toxic, anti-inflammatory seleno-organic compound, ebselen (PZ 51). When ethanolic extracts of the medium of stimulated cells were analysed by HPLC, a dose-dependent inhibition by ebselen of LTB4 formation with a concomitant decrease of 5-HETE production was found. Half-maximum inhibition was observed at 20 mumoles/l ebselen. Similar findings were obtained after analysis of chloroform extracts of both cells and medium using a different HPLC system. Under these conditions, enhanced 5-HETE formation was associated with reduced production of LTB4 and other di-HETE isomers, when purified glutathione peroxidase + GSH were present. We conclude that the reported GSH peroxidase-like activity of ebselen, catalysing the reduction of 5-HPETE to 5-HETE, can not account for our findings. Therefore, the lipoxygenase reaction itself apparently represents the site of inhibition of LTB4 formation by ebselen.
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