title: Quantification of the major urinary metabolite of PGE2 by a liquid chromatographic/mass spectrometric assay: determination of cyclooxygenase-specific PGE2 synthesis in healthy humans and those with lung cancer.
abstract: Prostaglandin (PG)E2 is a major cyclooxygenase (COX) product that is important in human physiology and pathophysiology. Quantification of systemic PG production in humans is best assessed by measuring excreted urinary metabolites. Accurate and easy-to-perform assays to quantify the major urinary metabolite of PGE2, 11alpha-hydroxy-9,15-dioxo-2,3,4,5-tetranor-prostane-1,20-dioic acid (PGE-M), do not exist. We now report the development of a robust and facile method to measure urinary PGE-M excretion in humans using stable isotope dilution techniques employing liquid chromatography/tandem mass spectrometry (LC/MS/MS). Concentrations of the metabolite in urine from healthy humans are nearly twofold greater in men than in women (10.4+/-1.5 vs. 6.0+/-0.7 ng/mg creatinine). Levels of PGE-M in healthy humans are suppressed significantly not only by the nonselective COX inhibitor ibuprofen but also by the COX-2 selective inhibitor rofecoxib, suggesting that the majority of PGE2 formed in vivo is derived from COX-2. Increased COX-2 expression and increased PGE2 production are associated with malignancy. Levels of PGE-M were found to be greatly increased in humans with unresectable non-small cell cancer of the lung, and this increase is dramatically reduced by administration of the COX-2 inhibitor celecoxib, implying that COX-2 contributes significantly to the overproduction of PGE2. In summary, quantification of PGE-M using LC/MS/MS provides a facile and accurate method to assess PGE2 formation in human physiological and pathophysiological processes.
authors.affiliation: Division of Clinical Pharmacology, Department of Medicine and Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
authors.forename: Laine J
authors.initials: LJ
authors.lastname: Murphey
authors.forename: Myles K
authors.initials: MK
authors.lastname: Williams
authors.forename: Stephanie C
authors.initials: SC
authors.lastname: Sanchez
authors.forename: Loretta M
authors.initials: LM
authors.lastname: Byrne
authors.forename: Ildiko
authors.initials: I
authors.lastname: Csiki
authors.forename: John A
authors.initials: JA
authors.lastname: Oates
authors.forename: David H
authors.initials: DH
authors.lastname: Johnson
authors.forename: Jason D
authors.initials: JD
authors.lastname: Morrow
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism / Q000652:urine*; D016022:Case-Control Studies; D002853:Chromatography, Liquid; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D015232:Dinoprostone / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D006262:Health; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism / Q000652:urine*; D008565:Membrane Proteins; D015394:Molecular Structure; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D011453:Prostaglandins / Q000737:chemistry / Q000378:metabolism / Q000652:urine*; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D008565:Membrane Proteins; D011453:Prostaglandins; C060526:7-hydroxy-5,11-dioxotetranorprostane-1,16-dioic acid; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone