FOXO1 and Hyperglycemia: Different external or internal stimuli induce the activation of the corresponding signalling pathways to coordinate with the PXR/ALAS1 axis, such as the hepatocyte nuclear factor 4 (HNF4) pathway, which is sensitive to a growth hormone pulse: the forkhead box protein O1 (FOXO1) pathway, which is sensitive to insulin; and the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) pathway, which is sensitive to hyperglycaemia [12, 14].