AKT1 and Insulin resistance: Indeed, treatment with a chemical chaperone, 4-phenyl butyric acid (PBA), restored hepatic PRSS8 levels and improved insulin resistance, which was assessed by a glucose tolerance test (GTT) and pyruvate tolerance test (PTT), and insulin-stimulated Akt phosphorylation, via the amelioration of ER stress (Fig. 1c,d).