GW-0742 vs Sobetirome (GC-1)

Metabolic

Metabolic

Research Only

Research Only

GW-0742 is a high-affinity, highly selective agonist of human PPARδ (EC50 = 1.1 nM for hPPARδ transactivation vs ~1.1 µM for hPPARα and ~2 µM for hPPARγ), conferring ~1000-fold selectivity for PPARδ over the other PPAR subtypes. Upon activation, PPARδ heterodimerizes with RXR and binds PPAR-response elements (PPREs) to alter transcription of genes governing fatty-acid oxidation, glucose utilization, and inflammatory signaling. In mice, however, GW-0742-induced hepatomegaly, hepatic/skeletal-muscle peroxisome proliferation, and skeletal myopathy were shown to be predominantly mediated by off-target PPARα cross-activation rather than PPARδ—a mechanism-based toxicity concern at animal-study exposures.

Sobetirome acts as an agonist at thyroid hormone receptor beta (TRβ) with substantially reduced affinity for TRα, conferring tissue-selective thyromimetic activity. Structural features—an oxyacetic acid moiety and absence of the amino group found in T3—underlie its subtype selectivity in both binding and activation. In hypothyroid mice, this TRβ selectivity produced lipid-lowering effects comparable to T3 without the cardiac chronotropic (heart-rate) increase driven by TRα, supporting the design goal of metabolic benefit with reduced cardiac risk.