Luciferase activity in HeLa cells transfected with human PPARα, δ and γ cDNAs measured 24 h after addition of unesterified FA at indicated concentration. Values represent % of transactivation values obtained in presence of the positive control Wy14,643 at 10 μM for PPARα, and of BRL49653 at 1 μM for PPARγ and PPARδ, taken as 100%. Significant activation is considered >50% of Wy14,643 for PPARα; >75% of BRL49653 for PPARγ and >100% of BRL49653 for PPARδ. Under the assay conditions employed, inhibition values could not be determined. Values represent mean of 3 replicates in independent experiments, with 4 replicates in each experiment.