title: Differential inhibition of prostaglandin endoperoxide synthase (cyclooxygenase) isozymes by aspirin and other non-steroidal anti-inflammatory drugs.
abstract: Murine prostaglandin endoperoxide (PGH) synthase-1 and PGH synthase-2 expressed in cos-1 cells were found to be differentially sensitive to inhibition by common nonsteroidal anti-inflammatory drugs (NSAIDs). Aspirin completely inhibited bis-oxygenation of arachidonate by PGH synthase-1; in contrast, aspirin-treated PGH synthase-2 metabolized arachidonate primarily to 15-hydroxyeicosatetraenoic acid (15-HETE) instead of PGH2. ID50 values were determined for a panel of common NSAIDs by measuring instantaneous inhibition of cyclooxygenase activity using an oxygen electrode. Among common NSAIDs tested, indomethacin, sulindac sulfide, and piroxicam preferentially inhibited PGH synthase-1; ibuprofen, flurbiprofen, and meclofenamate inhibited both enzymes with comparable potencies; and 6-methoxy-2-naphthylacetic acid preferentially inhibited PGH synthase-2. These results demonstrate that the two PGH synthases are pharmacologically distinct and indicate that it may be possible to develop isozyme-specific cyclooxygenase inhibitors useful both for anti-inflammatory therapy and for delineating between the biological roles of the PGH synthase isozymes.
authors.affiliation: Department of Biochemistry, Michigan State University, East Lansing 48824.
authors.forename: E A
authors.initials: EA
authors.lastname: Meade
authors.forename: W L
authors.initials: WL
authors.lastname: Smith
authors.forename: D L
authors.initials: DL
authors.lastname: DeWitt
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D001241:Aspirin / Q000494:pharmacology*; D002460:Cell Line; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D006893:Hydroxyeicosatetraenoic Acids / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors*; D007700:Kinetics; D051379:Mice; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D016861:Cyclooxygenase Inhibitors; D006893:Hydroxyeicosatetraenoic Acids; D007527:Isoenzymes; C025984:15-hydroxy-5,8,11,13-eicosatetraenoic acid; D011451:Prostaglandin-Endoperoxide Synthases; D001241:Aspirin; D007213:Indomethacin