Glucose is one of your body's preferred forms of energy. Some cells, such as brain cells, the cornea and lens in the eye and red blood cells, almost exclusively use glucose for fuel. The liver has an important role in regulating blood glucose levels and can increase or decrease blood glucose levels depending on the body's energy needs.
Glycogenesis
One of the ways that the liver controls blood glucose levels is through the synthesis of glycogen. Glycogen is formed when your body has excesses of the sugars fructose, glucose and galactose, RnCeus.com states. Glycogen is essentially made of many different sugar molecules linked together into large branched structures. Glycogen requires some energy to manufacture, so it is only made when there is extra sugar and energy present, the Elmhurst Virtual Chembook notes.
Liver and Insulin
The liver only makes glycogen when there is extra carbohydrates in the blood stream. The production of glycogen is controlled by the hormone insulin, which is secreted by the pancreas when blood glucose levels rise. Insulin has many different effects on the liver. It activates an enzyme in liver cells which chemically modify glucose so it is "trapped" in the liver cell, Colorado State University reports. Insulin also activates enzymes that convert sugars into glycogen.
Glycogenlysis
Glycogen primarily serves as a readily access reserve of glucose for the body. When blood glucose levels fall, the liver is able to convert the glycogen back into glucose. This process, is also controlled by hormones. When blood glucose levels drop, the pancreas secretes a hormone known as glucagon which stimulates the liver to break down glycogen. Similarly, epinephrine or adrenaline can make the liver make more glucose. Both of these hormones also block the synthesis of glycogen.
Gluconeogenesis
When blood glucose levels are low and the liver does not have enough glycogen to restore them, a process known as gluconeogenesis may start. Gluconeogenesis is the synthesis of glucose from non-carbohydrate sources, such as lactic acid and some amino acids, the Elmhurst Virtual Chembook explains. Many of the steps involved in gluconeogenesis are the exact opposite of the steps needed to turn glucose into energy. The main site of gluconeogenesis is the liver, though this process can also occur in the kidneys, brain and the muscles.
