title: Catabolism of leukotriene B5 in humans.
abstract: Human neutrophils, enriched by dietary supplementation with eicosapentaenoic acid, form leukotriene (LT)B5 in addition to LTB4 upon stimulation. LTB5 is one order of magnitude less biologically active than the potent chemokinetic and chemoattractant LTB4. Catabolites of LTB5 have not yet been characterized in vitro and ex vivo. It is unknown whether catabolism of LTB5 interferes with catabolism of LTB4. This report describes catabolism of LTB5 to 20-OH-LTB5, which in turn is catabolized to 20-COOH-LTB5. The structures of the two catabolites were established by UV-absorbance, behavior on reverse-phase high-performance liquid chromatography, enzymatic analysis of human neutrophils, and gas chromatography-mass spectrometry. In vitro, formation of LTB4 was delayed and formation of its catabolites was depressed by exogenous eicosapentaenoic acid. By supplementing the diet of six volunteers with 5 g eicosapentaenoic acid/day for 7 days, eicosapentaenoic acid quadrupled in neutrophil phospholipid fatty acids. Consequently, LTB5, 20-OH-LTB5, and 20-COOH-LTB5 were detected ex vivo. In contrast to the findings in vitro, however, levels of LTB4, 20-OH-LTB4, and 20-COOH-LTB4 were unaltered by the dietary intervention. Thus, in vitro, but not ex vivo, addition of eicosapentaenoic acid, and subsequent formation of LTB5, impeded catabolism of proinflammatory LTB4.
authors.affiliation: Medizinische Klinik Innenstadt, University of Munich, FRG.
authors.forename: C
authors.initials: C
authors.lastname: von Schacky
authors.forename: C
authors.initials: C
authors.lastname: Fahrer
authors.forename: S
authors.initials: S
authors.lastname: Fischer
mesh_terms: D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D003060:Cod Liver Oil / Q000008:administration & dosage; D015118:Eicosapentaenoic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D007476:Ionophores / Q000378:metabolism; D007700:Kinetics; D007975:Leukotriene B4 / Q000378:metabolism* / Q000031:analogs & derivatives; D008297:Male; D013058:Mass Spectrometry; D009504:Neutrophils / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet
chemical_list: D007476:Ionophores; D007975:Leukotriene B4; D003060:Cod Liver Oil; C040212:leukotriene B5; D015118:Eicosapentaenoic Acid