Lipoxin A₄-d₅(LXA₄-d₅) contains five deuterium atoms at the 19, 19', 20, 20, and 20 positions. It is intended for use as an internal standard for the quantification of LXA₄by GC-or LC-mass spectrometry (MS). LXA₄is a trihydroxy fatty acid containing a conjugated tetraene, produced by the metabolism of 15-HETE or 15-HpETE with human leukocytes.¹LXA₄is equipotent to leukotriene B₄(LTB₄) in inducing superoxide generation in human neutrophils at 0.1 µM.²LXA₄is associated with several other biological functions including leukocyte activation, chemotaxis effects, natural killer cell inhibition, and monocyte migration and adhesion.^2,3,4

1.Serhan, C.N., Nicolaou, K.C., Webber, S.E., et al.Lipoxin A. Stereochemistry and biosynthesisJ. Biol. Chem.261(35)16340-16345(1986) 2.Serhan, C.N., Hamberg, M., and Samuelsson, B.Lipoxins: Novel series of biologically active compounds formed from arachidonic acid in human leukocytesProc. Natl. Acad. Sci. U.S.A.81(17)5335-5339(1984) 3.Ramstedt, U., Serhan, C.N., Nicolaou, K.C., et al.Lipoxin A-induced inhibition of human natural killer cell cytotoxicity: Studies on stereospecificity of inhibition and mode of actionJ. Immunol.138(1)266-270(1987) 4.Maddox, J.F., and Serhan, C.N.Lipoxin A4 and B4 are potent stimuli for human monocyte migration and adhesion: Selective inactivation by dehydrogenation and reductionJ. Exp. Med.183(1)137-146(1996)