Arachidonic acid metabolism by rabbit synovial cells in culture. Studies of non-cyclooxygenase pathways.
We have investigated arachidonic acid (20:4) metabolism by rabbit synovial cells in culture. The lipoxygenase products 5-HETE, 12-HETE and 15-HETE were not detected, despite the presence of a cyclooxygenase inhibitor sodium meclofenamate (20 microM), nor after incubation with ionophore A23187 (1 microM), 20:4 (10 microM), prostaglandin E2, (1 microM), N-formylmethionylleucylphenylalanine (0.01 microM), or murine spleen cell-conditioned medium. [3H]20:4 (10 microM) was incorporated into phospholipids, triacylglycerols and diacylglycerols. A majority of the 3H content of phosphatidylinositol/phosphatidylserine and of diacylglycerols was already present at 1 min, in contrast to the slower accumulation of 3H in triacylglycerols, phosphatidylcholine and phosphatidylethanolamine. The diacylglycerol fraction contained sn-glycerol-1-acyl-2-20:4. These observations are consistent with phospholipase C activity in synovial cells under those culture conditions. The products generated by these enzymes may play important roles in the physiological processes of synovium.
D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism*; D002478:Cells, Cultured; D055598:Chemical Phenomena; D002621:Chemistry; D002855:Chromatography, Thin Layer; D004075:Diglycerides / Q000096:biosynthesis; D005260:Female; D008084:Lipoxygenase / Q000302:isolation & purification*; D009504:Neutrophils / Q000378:metabolism; D010740:Phospholipases / Q000302:isolation & purification*; D011817:Rabbits; D013583:Synovial Membrane / Q000201:enzymology / Q000378:metabolism*; D010738:Type C Phospholipases / Q000302:isolation & purification*
D001095:Arachidonic Acids; D004075:Diglycerides; D008084:Lipoxygenase; D010740:Phospholipases; D010738:Type C Phospholipases