Glikogénraktárak

Glikogénraktárak, also known as glycogen stores, are the primary form of glucose storage in animals, fungi, and bacteria. In humans, the majority of glycogen is stored in the liver and muscles. Liver glycogen plays a crucial role in maintaining blood glucose homeostasis, releasing glucose into the bloodstream to ensure a steady supply for all tissues, especially the brain. Muscle glycogen, on the other hand, serves as a readily available energy source specifically for muscle contraction during physical activity.

Glycogen is a branched polysaccharide composed of glucose units linked together by alpha-1,4 glycosidic bonds, with alpha-1,6 branches occurring every 8-12 glucose residues. This branched structure allows for rapid synthesis and breakdown. The synthesis of glycogen, known as glycogenesis, is stimulated by insulin when blood glucose levels are high. Conversely, the breakdown of glycogen into glucose, called glycogenolysis, is activated by hormones like glucagon and adrenaline when blood glucose levels drop or during exercise.

The capacity of glycogen storage is limited. Once these stores are filled, excess glucose can be converted into fat for longer-term energy storage. Disorders affecting glycogen metabolism, known as glycogen storage diseases, can lead to a variety of health problems due to the inability to properly store or mobilize glucose.