noun, plural: glycogens
Glycogen is a type of polysaccharide that occurs in animals. It is sometimes referred to as "animal starch." It is an analogue of starch in plants, only it is less branched. The starch in plants and the glycogen in animals are complex carbohydrates that store excess glucose. In animals, the glycogen is one of the main forms of energy reserves (the other being triglycerides or body fat).
Under the microscope, glycogen has a characteristic asterisk or star appearance. It is a multibranched polysaccharide. When the body needs energy, glycogen is broken down into glucose with glucagon. It is produced mainly in the liver and the skeletal muscle cells. Small amounts of glycogen can be found in the kidneys, some glial cells in the brain, and white blood cells. The uterus also stores glycogen during pregnancy to nourish the embryo.
- animal starch