Biochimica et Biophysics Acta, 194 (1984) 403-410 Elsevier BBA 51684 403 zyxwvutsr ABACHIDONIC ACID METABOLIC PATHWAYS IN THE RABBIT PERICARDIUM ATSUSHI HONDA *, AUBREY R. MORRISON, EDWARD R. MCCLUSKEY and PHILIP NEEDLEMAN ** Department of Pharmacology and Medicine, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110 (U.S.A.) (Received December 15th, 1983) Key words: Arachidonate metabolism; Prostacyclin catabolism; Prostaglandin; Eicosanoik (Rabbit pericardium) Minced rabbit pericardium actively converts [l-‘4C]arachidonic acid into the known prostaglandins (6[l- “C]ketoprostaglandin F,=, [l- 14C]prostaghmdin E, and [ l-14C]prostagIandin F,,) and into several unidenti- fied metabolites. The major metabolite was separated by C ,s reverse-phase high-pressure liquid chromatogra- phy (HPLC) and identified by gas chromatography-mass spectrometry (GC-MS) to be 6,15-[l-‘4C]diketo- 13,14-dihydroprostaghmdin F,,. The other nonpolar metabolites were 15-I l-‘4C]hydroxy-5,8,11,13-eicosa- tetraenoic acid (15-HETE), ll-(l-14C]hydroxy-5,8,12,14-eicosatetraenoic acid (ll-HETE) and 12-(1-‘4C]hy- droxy-5,8,10,16eicosatetraenoic acid (1ZHETE). Arachidonic acid metabolites actively produced by the pericardium could influence the tone of surface blood vessels on the myocardium: Introduction Prostacyclin is the major prostaglandin released from the isolated perfused heart [l-3]. The primary site of prostacyclin biosynthesis is the coronary vasculature [l-3,4,5]. However, recent evidence has revealed the production of prostacyclin by heart valves [6], endocardium [6], epicardium and peri- cardium (7-91. The pericardium is a more active producer of prostacyclin than aorta [7] or slices of myocardium [ 91. We have become increasingly interested in the role of extravascular sources of prostaglandins in the pericardiac cavity, since metabolites produced by the pericardium have the potential to influence * Dr. A. Honda is an NIH Fogarty International Fellow and his permanent address is Tokyo College of Pharmacy, Tokyo 192-03, Japan ** To whom reprint requests should be addressed. Abbreviations: ETYA, 5,8,11,14_eicosatetraynoic acid; HETE, hydroxyeicosatetraenoic acid; HPETE, hydroperoxyeico- satetraenoic acid; HHT, 12-hydroxyheptadecatrienoic acid; Me, Si, trimethylsilyl. 0005-2760/84/$03.00 6 1984 Elsevier Science Publishers B.V. epicardial coronary vessels in normal or patho- physiological situations. We report here arachidonic acid metabolic pathways in the rabbit pericardium on the basis of [1-‘4C]arachidonic acid metabolites identified. Materials and Methods Materials The following commercial materials were used: [l-‘4C]arachidonic acid (56 mCi/mmol) and [l- “C]dihomo-y-linolenic acid (54.9 mCi/ mmol) were from New England Nuclear. BSTFA (bis(tri- methylsilyl)trifluoroacetamide) and methoxyamine hydrochloride were from Pierce Chemical Co. In- domethacin was a gift from Merck Sharp and Dohme Research Laboratories, West Point, PA. An etheral solution of diazomethane was pre- pared from Diazald@, Aldrich Chemical Co., Milwaukee, WI. [1-‘4C]Prostaglandin H, was pre- pared from [1-‘4C]arachidonic acid as described previously [lo]. Prostaglandin standards, 6,15diketopros-