title: Analogs of leukotriene B4: effects of modification of the hydroxyl groups on leukocyte aggregation and binding to leukocyte leukotriene B4 receptors.
abstract: The syntheses and agonist and binding activities of 5(S)-hydroxy- 6(Z), 8(E), 10(E), 14(Z)-eicosatetraenoic acid (12-deoxy LTB4), 5(S), 12(S)-dihydroxy-6(Z), 8(E), 10(E), 14(Z)-eicosatetraenoic acid (12-epi LTB4), 12(R)-hydroxy-6(Z), 8(E), 10(E), 14(Z)-eicosatetraenoic acid (5-deoxy LTB4), 5(R), 12(S)-dihydroxy-6(Z), 8(E), 10(E), 14(Z)-eicosatetraenoic acid (5-epi LTB4), 6(Z), 8(E), 10(E), 14(Z)-eicosatetraenoic acid (5, 12-deoxy LTB4) are described. These leukotriene B4 analogs were all able to aggregate rat leukocytes and compete with [3H]-leukotriene B4 for binding to rat and human leukocyte leukotriene B4 receptors with varying efficacy. The analog in which the 12-hydroxyl group was removed was severely reduced both in agonist action (aggregation) and binding. The epimeric 12-hydroxyl analog demonstrated better agonist and binding properties than the analog without a hydroxyl at this position. In contrast, in the case of the 5-hydroxyl the epimeric hydroxyl analog had greatly reduced agonist and binding activities while the 5-deoxy analog demonstrated potency only several fold less than leukotriene B4 itself. The dideoxy leukotriene B4 analog was more than a thousand fold less active than leukotriene B4 as an agonist and in binding to the leukotriene B4 receptor. These results show that binding to the leukocyte leukotriene B4 receptor requires a hydroxyl group at the 12 position in either stereochemical orientation but that the presence of a hydroxyl at the 5 position is less important. However, the epimeric C5 leukotriene B4 analog clearly interacts unfavourably with the binding site of the leukotriene B4 receptor.
mesh_terms: D000818:Animals; D002449:Cell Aggregation / Q000187:drug effects; D002462:Cell Membrane / Q000276:immunology; D006801:Humans; D007700:Kinetics; D007962:Leukocytes / Q000166:cytology / Q000276:immunology*; D007975:Leukotriene B4 / Q000138:chemical synthesis / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D011971:Receptors, Immunologic / Q000378:metabolism*; D018102:Receptors, Leukotriene B4; D013329:Structure-Activity Relationship
chemical_list: D011971:Receptors, Immunologic; D018102:Receptors, Leukotriene B4; D007975:Leukotriene B4