IRS1 and fetal growth restriction: Compared to the NBW piglets, IUGR enhanced (p < 0.05) the hepatic Irs1, Pik3c3, Gsk3a, Fabp1, and Srebp mRNA expressions and reduced (p < 0.05) the hepatic Gys2, Lxr and Ppara mRNA expressions (Figure 3a,b).