Figure 2. Effects of PPAR agonists and antagonists on PTGS2 levels.

(a) Bovine endometrial stromal cells were cultured with or without arachidonic acid (50 μM) and the synthetic PPARα agonists WY14643 (50 μM), ciprofibrate (50 μM) and methylclofenapate (50 μM), the PPARδ agonists bezafibrate (50 μM) and SB400455 (50 nM), and the PPARγ agonists ciglitazone (50 μM) and pioglitazone (1 μM). These concentrations have been shown to be effective in other cell types. PTGS2 was measured by immunoblotting after 6 h. The effects of WY14643 and ciprofibrate were statistically significant (P<0.05); the effect of methylclofenapate was not significant at 6 h, but reached significance (P<0.02) between 6 and 24 h (results not shown). Results were obtained from three experiments. (b) Effects of the PPARα/PPARγ agonist NSAIDs on PTGS2 levels. Closed bars, PTGS2 levels; open bars, PGE₂ production. Stromal cells were cultured for 6 h with or without arachidonic acid (AA; 50 μM), NS398 (50 μM) or indomethacin (10 μM). PTGS2 level was increased by arachidonic acid (P<0.001), NS398 (P<0.001) and indomethacin (P<0.01). The increase in PGE₂ production in response to arachidonic acid was blocked by NSAIDs. Results were obtained from four experiments. (c) Time course of the effects of arachidonic acid (50 μM; open bars) and indomethacin (10 μM; closed bars) on PTGS2 levels. The results were identical. (d) Effects of the PPARα/PPARδ/PPARγ agonist PGA₁ on PTGS2 levels. Bovine endometrial stromal cells were cultured for 6 h with or without arachidonic acid (50 μM), PGA₁ (0.3 μM) or PGA₁ (3 μM). PTGS2 levels were increased in the presence of PGA₁ (P<0.001).