Glicogenólise

Glicogenólise is a metabolic process that involves the breakdown of glycogen into glucose. This process occurs primarily in the liver and muscles, serving as a crucial mechanism for maintaining blood glucose levels and providing energy during periods of fasting or increased physical activity. Glycogen, a complex carbohydrate, is stored in these tissues as a readily available source of glucose.

The breakdown of glycogen begins with the enzyme glycogen phosphorylase, which cleaves glucose units from the glycogen chain. This process releases glucose-1-phosphate, which is then converted to glucose-6-phosphate by the enzyme phosphoglucomutase. In the liver, glucose-6-phosphate can be further dephosphorylated by glucose-6-phosphatase to yield free glucose, which is then released into the bloodstream to be utilized by other tissues. In muscle cells, glucose-6-phosphate is directly used for energy production through glycolysis, as muscle cells lack the enzyme glucose-6-phosphatase.

Hormonal regulation plays a significant role in controlling glicogenólise. Glucagon, released by the pancreas when blood glucose levels are low, stimulates glycogenolysis in the liver. Epinephrine, also known as adrenaline, released during stress or exercise, promotes glycogenolysis in both the liver and muscles, providing a rapid surge of glucose for energy. Conversely, insulin, released when blood glucose levels are high, inhibits glycogenolysis and promotes glycogen synthesis, thus lowering blood glucose. This intricate hormonal control ensures that glucose is available when needed and stored efficiently when in excess.