FIGURE 4.

Hepatic insulin signaling. AKT signaling is central to hepatocellular insulin action. Fast effects include activation of the glycogen and protein synthetic machinery. Slower transcriptionally mediated effects include upregulation of glucokinase, dimunition of gluconeogenic capacity, and stimulation of de novo lipogenic capacity. Green circles and arrows represent activating events; red circles and arrows represent inhibitory events. IRS, insulin receptor substrate; GSK3, glycogen synthase kinase 3; PI3K, phosphoinositide-3-kinase; PP1, protein phosphatase 1; GPAT, glycerol-3-phosphate acyltransferase; G6PC, glucose-6-phosphatase; PCK1, phosphoenolpyruvate carboxykinase; SREBP1c, sterol regulatory element binding protein 1c; FAS, fatty acid synthase.