Phospholipase A2 activation by interleukin 1: release and metabolism of arachidonic acid by IL 1-stimulated rabbit chondrocytes.
Treatment of rabbit chondrocytes with natural or recombinant human IL 1 results in a dramatic dose-dependent increase in intracellular phospholipase A2 (PLA2) activity and subsequent secretion of this enzyme into the intracellular millieu. PLA2 activity is detectable as early as 1 hr after IL 1 stimulation and is maximal by 24 hr. In the present study, we have characterized more fully the relationship between PLA2 activation and arachidonate metabolism in these cells. IL 1 treatment of chondrocytes which had been prelabeled with [14C]arachidonic acid resulted in an enhanced release of free arachidonic acid identified by thin-layer chromatography. Moreover, the arachidonic acid liberated was subsequently metabolized exclusively to PGE2; no significant increases in the production of 6-keto PGF1 alpha, LTB4, LTC4, 12-HETE or 15-HETE were observed following IL 1 stimulation.
D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism; D002358:Cartilage, Articular / Q000187:drug effects* / Q000378:metabolism; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D007375:Interleukin-1 / Q000494:pharmacology*; D010740:Phospholipases / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D011817:Rabbits
D001095:Arachidonic Acids; D007375:Interleukin-1; D016718:Arachidonic Acid; D010740:Phospholipases; D010741:Phospholipases A; D054467:Phospholipases A2