SecinH3

SecinH3 is an antagonist of cytohesins with IC₅₀s of 5.4 μM, 2.4 μM, 5.4 μM, 5.6 μM, 5.6 μM and 65 μM for hCyh1, hCyh2, mCyh3, hCyh3, drosophila steppke and yGea2-S7, respectively. IC50 & Target: IC50: 5.4 μM (hCyh1)，2.4 μM (hCyh2)，5.4 μM (mCyh3)，5.6 μM (hCyh3)，5.6 μM (drosophila steppke), 65 μM (yGea2-S7)^[1] In Vitro: SecinH3 is a Sec7-specific guanine nucleotide exchange factor (GEF) inhibitor with preference for the small GEFs of the cytohesin family. SecinH3 almost completely blocks the insulin-dependent transcriptional repression of IGFBP1 with an IC₅₀ of 2.2 μM. Insulin-stimulated translocation of ARF6 to the plasma membrane is also inhibited by SecinH3. It is found that SecinH3 inhibits the insulin-dependent phosphorylation of Akt and FoxO1A in a concentration-dependent manner. Insulin-induced exclusion of FoxO1A from the nucleus is completely prevented by SecinH3. The binding of IRS1 to the insulin receptor is also inhibited by SecinH3^[1]. In Vivo: Compare to mice fed the same chow without SecinH3, the expression levels of the insulin-repressed gluconeogenic genes are elevated, whereas the insulin-induced glycolytic genes are reduced in SecinH3-treated mice. Insulin-stimulated Akt phosphorylation is also inhibited in SecinH3-treated mice. The expression of the genes for two key enzymes of mitochondrial β-oxidation, carnitine palmitoyltransferase 1a (Cpt1a) and hydroxyacyl-CoA dehydrogenase (Hadha), both of which are repressed by insulin, is increased in the SecinH3-treated mice. It is found significantly increased levels of serum insulin with slightly elevated glucose concentrations in SecinH3-treated mice. Accordingly, 3-hydoxybutyrate is increased in the serum of SecinH3-treated mice^[1].