SR9009 is a REV-ERBα/β agonist with IC₅₀s of 670 nM and 800 nM for REV-ERBα and REV-ERBβ, respectively. IC50 & Target: IC50: 670 nM (Rev-ErbBα), 800 nM (Rev-ErbBβ)^[1] In Vitro: SR9009 dose-dependently increases the REV-ERB-dependent repressor activity assessed in HEK293 cells expressing a chimeric Gal4 DNA Binding Domain (DBD)-REV-ERB ligand binding domain (LBD)α or β and a Gal4-responsive luciferase reporter (SR9009: REV-ERBα IC₅₀=670 nM, REV-ERBβ IC₅₀=800 nM). SR9009 potently and efficaciously suppresses transcription in a cotransfection assay using full-length REV-ERBα along with a luciferase reporter driven by the Bmal1 promoter (IC₅₀=710 nM). SR9009 suppresses the expression of BMAL1 mRNA in HepG2 cells in a REV-ERBα/β-dependent manner. Direct binding of the SR9009 to REV-ERBα is also confirmed using circular dichrosim analysis (K_d=800 nM)^[1]. In Vivo: While the stress of handling and twice-daily injections caused weight loss in vehicle-treated controls, weight loss of SR9009-treated animals is 60% greater. SR9009 (100 mg/kg ,i.p.) treated mice exhibit a more severe reduction in adiposity. Plasma non-esterified fatty acids (NEFA) are also reduced (23%) along with plasma glucose (19%) in the SR9009 treated animals. In the white adipose tissue (WAT) , SR9009 treatment results in a decrease in expression of genes encoding enzymes involved in triglyceride (TG) synthesis as is also observed in lean mice^[1].