(Rac)-SAG, an isoform of SAG, is a potent Smoothened (Smo) receptor agonist (EC₅₀ = 3 nM; Kd = 59 nM) that activates the Hedgehog signaling pathway and counteracts Cyclopamine's inhibition of Smo [1] [2] [3].

SAG is a chemical compound that, at concentrations ranging from 0.1 nM to 100 μM over 30 hours, induces firefly luciferase expression in Shh-LIGHT2 cells with an EC50 of 3 nM, and then inhibits expression at higher concentrations [1]. At concentrations between 1 and 1000 nM over 1 hour, SAG competes with BODIPY-cyclopamine for binding to the SAG/Smo complex in Cos-1 cells expressing Smo, resulting in an apparent dissociation constant (Kd) of 59 nM [1]. At 100 nM, SAG suppresses the inhibition of activation in the ShhN-induced Robotnikinin pathway [2]. When applied at 250 nM for 48 hours, SAG significantly increases the expression of SMO mRNA and protein in MDAMB231 cells [3]. Furthermore, at the same concentration of 250 nM over 24 and 48 hours, SAG enhances CAXII mRNA expression in MDAMB231 cells under normoxia and hypoxia conditions over 24 hours [3]. Additionally, SAG at 250 nM for 24 hours promotes MDAMB231 cell migration [3].

In CD-1 mice, SAG (1.0 mM) predominantly induces enhanced osteogenesis at the defect boundary, significantly increasing BV/TV at eight weeks [4]. Additionally, SAG (15-20 mg/kg; ip) universally induces preaxial polydactyly in mice in a dose-dependent manner [5].