PPARβ/δ is thought to play a role in lipid homeostasis and glucose disposal by regulating genes involved in fatty acid oxidation, reverse cholesterol transport, and carbon substrate utilization in skeletal muscle. It has also been implicated in the progression of certain cancers. GSK3787 is an irreversible antagonist of PPARβ/δ (pIC50 = 6.6) with no measurable affinity for PPARα or PPARγ (pIC50 >5). At 1μM, it inhibits the expression of PPARβ/δ-regulated target genes, pyruvate dehydrogenase kinase 4 and carnitine palmitoyl transferase 1a, which are important for energy homeostasis in human skeletal muscle cells. GSK3787 (at 1 μM) also antagonizes agonist-induced expression of angiopoietin-like protein 4 in mouse fibroblasts, mouse keratinocytes, and human MCF-7, Huh7, and HepG2 cancer cell lines.