Metabolism of Glucose in Normal Patients

In patients without diabetes glucose levels are maintained within a small range.

When there is an excess of glucose, insulin triggers conversion of this excess initially to glycogen, which is stored in the liver. At higher levels of glucose, insulin converts to fatty acids in the liver – these are ultimately converted to triglycerides in adipocytes.

When the blood glucose level begins to fall, insulin levels also fall, and this process is reversed. This occurs initially via breakdown of glycogen (glycogenolysis) to release glucose from the liver, and once all the glycogen is utilised, by gluconeogenesis in which the hepatocytes produce glucose from non-carbohydrate substrates such as protein and fat. Therefore, during starvation or prolonged exercise gluconeogenesis maintains plasma glucose levels.

The pancreas secretes insulin at a background level but also surges in response to rises in glucose within the portal system.