How does the liver regulate blood glucose levels?

The liver regulates blood glucose levels through the processes of glycogenesis, glycogenolysis, and gluconeogenesis.

The liver plays a crucial role in maintaining the body's blood glucose levels within a narrow range, ensuring a constant supply of energy to the body's cells. This is achieved through three main processes: glycogenesis, glycogenolysis, and gluconeogenesis.

Glycogenesis is the process of converting glucose into glycogen for storage. When blood glucose levels are high, such as after a meal, the pancreas releases insulin. Insulin signals the liver to take up glucose from the bloodstream and convert it into glycogen. This process reduces the amount of glucose in the blood, preventing hyperglycaemia (high blood glucose levels).

Glycogenolysis is the breakdown of glycogen into glucose. When blood glucose levels are low, such as during fasting or between meals, the pancreas releases glucagon. Glucagon signals the liver to break down stored glycogen into glucose, which is then released into the bloodstream. This process increases the amount of glucose in the blood, preventing hypoglycaemia (low blood glucose levels).

Gluconeogenesis is the production of glucose from non-carbohydrate sources, such as amino acids and glycerol. This process occurs primarily when the body is fasting or during prolonged exercise, when glycogen stores are depleted. Gluconeogenesis ensures that the body has a constant supply of glucose, even when dietary intake is low or energy demands are high.

In addition to these processes, the liver also plays a role in the regulation of blood glucose levels through the metabolism of fructose and galactose, two other types of sugar. These sugars are converted into glucose in the liver and then either stored as glycogen or released into the bloodstream.

In summary, the liver is a key player in the regulation of blood glucose levels, ensuring that the body's cells have a constant supply of energy. It does this through the processes of glycogenesis, glycogenolysis, and gluconeogenesis, as well as the metabolism of other sugars.