RECOMBINANT TUMOR-NECROSIS-FACTOR AND INTERLEUKIN-1 BOTH STIMULATE HUMAN SYNOVIAL CELL ARACHIDONIC-ACID RELEASE AND PHOSPHOLIPID-METABOLISM

Stimulation of [3H]-arachidonic acid labeled human synovial cells with 3.0 .times. 10-10M recombinant interleukin-1 or tumor necrosis factor resulted in the release of incorporated radiolabel (41.1% and 27.7% respectively). Analysis of [3H]-arachidonic acid labeled phospholipids showed that interleukin-1 and tumor necrosis factor diminished [3H]-arachidonic acid in phosphatidylcholine, phosphatidylserine and phosphatidylinositol. Treatment of [3H]-arachidonic acid labeled cells with 10-3M dibutyryl cyclic AMP or 10-6M PGE2 did not affect spontaneous or stimulated [3H] arachidonic acid release significantly. These data show that recombinant interleukin-1 and tumor necrosis factor stimulate human synovial cell phospholipase activity in a similar manner and that this activity is not affected significantly by agents that elevate cyclic AMP.