Furthermore, skeletal muscle in postnatal UPI-induced IUGR/LBW rats shows downregulation of insulin receptor beta (IRβ) and reduced phosphorylation of phosphoinositide 3-kinase (PI3K)/Protein kinase (AKT) at serine 473 (phospho-AktSer473), while that in young-adult men born LBW shows reduced insulin-signaling proteins [20], indicating disruption in insulin signaling [33,34]. The gene discussed is AKT1; the disease is fetal growth restriction.