title: Pharmacology of MK-0591 (3-[1-(4-chlorobenzyl)-3-(t-butylthio)-5-(quinolin-2-yl-methoxy)- indol-2-yl]-2,2-dimethyl propanoic acid), a potent, orally active leukotriene biosynthesis inhibitor.
abstract: MK-0591 (3-[1-(4-chlorobenzyl)-3-(t-butylthio)-5-(quinolin-2-yl-methoxy)- indol-2-yl]-2,2-dimethyl propanoic acid, previously L-686,708) is a potent inhibitor of leukotriene (LT) biosynthesis in intact human and elicited rat polymorphonuclear leukocytes (PMNLs) (IC50 values 3.1 and 6.1 nM, respectively) and in human, squirrel monkey, and rat whole blood (IC50 values 510, 69, and 9 nM, respectively). MK-0591 had no effect on rat 5-lipoxygenase. MK-0591 has a high affinity for 5-lipoxygenase activating protein (FLAP) as evidenced by an IC50 value of 1.6 nM in a FLAP binding assay and inhibition of the photoaffinity labelling of FLAP by two different photoaffinity ligands. Inhibition of activation of 5-lipoxygenase was shown through inhibition of the translocation of the enzyme from the cytosol to the membrane in human PMNLs. MK-0591 was a potent inhibitor of LT biosynthesis in vivo, first, following ex vivo challenge of blood obtained from treated rats and squirrel monkeys, second, in a rat pleurisy model, and, third, as monitored by inhibition of the urinary excretion of LTE4 in antigen-challenged allergic sheep. Inhibition of antigen-induced bronchoconstriction by MK-0591 was observed in inbred rats pretreated with methysergide, Ascaris-challenged squirrel monkeys, and Ascaris-challenged sheep (early and late phase response). These results indicate that MK-0591 is a potent inhibitor of LT biosynthesis both in vitro and in vivo indicating that the compound will be suitable for assessing the role of leukotrienes in pathological situations.
authors.affiliation: Department of Pharmacology, Merck Frosst Centre for Therapeutic Research, Pointe Claire-Dorval, Québec, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Brideau
authors.forename: C
authors.initials: C
authors.lastname: Chan
authors.forename: S
authors.initials: S
authors.lastname: Charleson
authors.forename: D
authors.initials: D
authors.lastname: Denis
authors.forename: J F
authors.initials: JF
authors.lastname: Evans
authors.forename: A W
authors.initials: AW
authors.lastname: Ford-Hutchinson
authors.forename: R
authors.initials: R
authors.lastname: Fortin
authors.forename: J W
authors.initials: JW
authors.lastname: Gillard
authors.forename: J
authors.initials: J
authors.lastname: Guay
authors.forename: D
authors.initials: D
authors.lastname: Guévremont
mesh_terms: D058927:5-Lipoxygenase-Activating Proteins; D000284:Administration, Oral; D000818:Animals; D000941:Antigens / Q000008:administration & dosage; D001094:Arachidonate 5-Lipoxygenase / Q000187:drug effects / Q000378:metabolism; D001200:Ascaris / Q000276:immunology; D016084:Bronchoconstriction / Q000187:drug effects; D002352:Carrier Proteins / Q000378:metabolism / Q000494:pharmacology; D004347:Drug Interactions; D006801:Humans; D007211:Indoles / Q000097:blood / Q000494:pharmacology*; D007975:Leukotriene B4 / Q000096:biosynthesis* / Q000097:blood; D016859:Lipoxygenase Inhibitors; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism / Q000494:pharmacology; D011804:Quinolines / Q000097:blood / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012453:Saimiri
chemical_list: D058927:5-Lipoxygenase-Activating Proteins; C548592:ALOX5AP protein, human; C548594:Alox5ap protein, rat; D000941:Antigens; D002352:Carrier Proteins; D007211:Indoles; D016859:Lipoxygenase Inhibitors; D008565:Membrane Proteins; D011804:Quinolines; C078266:MK 0591; D007975:Leukotriene B4; D001094:Arachidonate 5-Lipoxygenase