title: Studies on the biosynthesis of leukotrienes in guinea pig lung in vitro by use of high-performance liquid chromatography.
abstract: The biosynthesis of leukotrienes (LTs) and 5-hydroxy-6,8,-11,14(E,Z,Z,Z)-eicosatetraenoic acid (5-HETE) in perfused guinea pig lung was studied by reversed phase-high-performance liquid chromatography (RP-HPLC). Perfusion of lungs with a 20 microM solution of ionophore A23187 for 25 minutes induced a sustained release of 5S-hydroxy-6R-S-cysteinylglycyl-7,9,11,14-(E,E,Z,Z)-eicosatetraenoic acid (LTD4) and 5S,12R-dihydroxy-6,8,10,14(Z,E,E,Z)-eicosatetraenoic acid (LTB4). The perfusion of 60 microM of arachidonic acid together with the ionophore only slightly increased the synthesis of LTD4 and LTB4 in comparison with the effect of the ionophore alone but markedly stimulated the release of 5-HETE that was not detectable under other experimental conditions. Immunologic challenge of the lung by continuous perfusion of ovalbumin to previously sensitized guinea pigs induced the release of 50 to 150 pM of LTB4 and 15 to 50 pM of LTD4 during a 25-minute period. Antigen was a less potent stimulus than the ionophore that caused the release of 500 to 900 pM of LTB4 and 100 to 250 pM of LTD4 during 25-minutes of perfusion. None of the above-mentioned metabolites were detected when lungs were perfused with arachidonic acid alone, indicating that the synthesis of 5-lipoxygenase products required activation of the lung. In addition to 5-lipoxygenase products, the cyclooxygenase products 12-hydroxy-5,8,10-(Z,E,E)-heptadecatrienoic acid and 12-keto-5,8,10-(Z,E,E)-heptadecatrienoic acid were analyzed by RP-HPLC in guinea pig lung perfusates. HPLC analysis provided quantitative data on the release of several arachidonic acid metabolites by lungs.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006168:Guinea Pigs; D007975:Leukotriene B4 / Q000096:biosynthesis*; D008168:Lung / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D013189:SRS-A / Q000096:biosynthesis*; D013997:Time Factors
chemical_list: D013189:SRS-A; D007975:Leukotriene B4; D000001:Calcimycin