GLUCOSE PRODUCTION AND UTILIZATION

The balance between glucose production and utilization is regulated by a network of hormones, neural path-ways, and metabolic signals. Insulin plays a pivotal role in this process. In the fasting state, insulin secretion is suppressed, which leads to increased gluconeogenesis in the liver and kidneys and increased glucose generation by the breakdown of liver glycogen. In the fed state, insulin released from pancreatic  β-cells reverses this process by inhibiting glycogenolysis and gluconeogenesis, enhancing peripheral glucose uptake and utilization, and reducing lipolysis and proteolysis. The net result is that excess glucose is converted into glycogen, triglycerides (TGs), and proteins.

When more glucose is present in liver cells than can be metabolized or stored as glycogen, insulin causes the excess glucose to be converted into FFAs. These FFAs are packaged as TGs in VLDL, transported in the blood in this form, and deposited as fat in adipose tissue.