glicogén

Glicogen is a polysaccharide that serves as the primary form of glucose storage in animals and fungi. It is a branched polymer composed of glucose units linked by alpha bonds. Specifically, glucose monomers are joined by alpha(1→4) glycosidic bonds in a linear chain, with alpha(1→6) glycosidic bonds forming branches at regular intervals. This branched structure is crucial for its function.

The liver and muscles are the main sites of glycogen storage. In the liver, glycogen acts as a reserve that can be released into the bloodstream to maintain blood glucose homeostasis between meals. This process is called glycogenolysis. In muscles, glycogen serves as a readily available source of glucose for energy production during muscle activity. Muscle glycogen cannot be directly released into the bloodstream; it is utilized by the muscle cells themselves.

The synthesis of glycogen from glucose is known as glycogenesis, and it occurs when blood glucose levels are high. Conversely, the breakdown of glycogen into glucose is called glycogenolysis, and it is stimulated by hormones such as glucagon and epinephrine when blood glucose levels fall or when energy is needed. Glycogen storage diseases are a group of rare genetic disorders that affect the body's ability to produce or break down glycogen, leading to various health problems.