Metabolism of 12-hydroperoxyeicosatetraenoic acid to vasodilatory trioxilin C3 by rabbit aorta. Biochim Biophys Acta 2003 Jun 20;1622(1):6-13
Date
06/28/2003Pubmed ID
12829255DOI
10.1016/s0304-4165(03)00097-7Scopus ID
2-s2.0-0037757519 (requires institutional sign-in at Scopus site) 16 CitationsAbstract
Arachidonic acid is metabolized by both the cyclooxygenase and lipoxygenase pathways by rabbit aorta. We investigated the metabolism of 12-hydroperoxyeicosatetraenoic acid by aortic homogenates and microsomes. Rabbit aortic homogenates were incubated in the presence of (14)C-arachidonic acid plus 12-lipoxygenase and analyzed by reversed-phase high-pressure liquid chromatography (HPLC). Under these experimental conditions, there was a (14)C-metabolite that migrated at 17.6 min. This (14)C-metabolite was not observed when aortic homogenates were incubated in the absence of 12-lipoxygenase. Similar results were obtained with aortic microsomes. Further analysis using a different HPLC solvent system resolved the (14)C-metabolite into a number of products. Gas chromatography/mass spectrometric (GC-MS) analysis of the major product (labeled peak 3) after conversion to the methyl ester-trimethylsilyl derivative showed two major compounds (compounds A and B) eluting at 13.99 and 14.14 min. The two compounds differed in the intensities of the 213 and 243 m/z ions with 243 being greater than 213 in compound A and the opposite in compound B (relative abundance 213 vs. 243; 100% vs. 43% for compound A and 5% vs. 100% for compound B). Based on the mass spectra, peak 3 contained two metabolites identified as the methyl ester-trimethylsilyl ether derivatives of 8,11,12-trihydroxyeicosatrienoic acid (trioxilin A(3)) and 8,9,12-trihydroxyeicosatrienoic acid (trioxilin C(3)). Biological activity of the mixture of two trioxilins isolated from aortic homogenates was tested in phenylephrine-precontracted aortas and found to produce concentration-dependent relaxations (maximal relaxation: 20.1+/-7.6%). Further testing with authentic trioxilin A(3) and C(3) revealed that trioxilin C(3) was the active metabolite (maximal relaxation: 16.6+/-1.3%). In conclusion, trioxilin C(3) acid was isolated and identified as a novel biologically active arachidonic acid metabolite formed by rabbit aorta when 12-lipoxygenase is supplied exogenously.
Author List
Pfister SL, Spitzbarth N, Nithipatikom K, Falck JR, Campbell WBAuthors
William B. Campbell PhD Professor in the Pharmacology and Toxicology department at Medical College of WisconsinSandra L. Pfister PhD Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
8,11,14-Eicosatrienoic AcidAnimals
Aorta
Chromatography, High Pressure Liquid
Gas Chromatography-Mass Spectrometry
In Vitro Techniques
Leukotrienes
Male
Rabbits
Vasodilation
Vasodilator Agents
