Biochemistry - Glycogenolysis

Excerpt

Glycogen, also known as animal starch, is a branched polysaccharide that serves as a reserve of carbohydrates in the body; it is stored in the liver and muscle and readily available as an immediate energy source. The formation of glycogen from glucose is known as glycogenesis, and the breakdown of glycogen to form glucose is called glycogen metabolism or glycogenolysis. Increased cyclic adenosine monophosphate (cAMP) catalyzes the breakdown of glycogen (glycogenolysis). The primary hormones that regulate the cycle of glycogenesis and gluconeogenesis are insulin, glucagon, and cortisol. Glycogenolysis is initiated by the action of a specific enzyme called phosphorylase, which yields glucose-1-phosphate (P). Glucose-1-P is an essential compound at the intersection of several metabolic pathways, such as glycolysis, glycogenesis, glycogenolysis, and gluconeogenesis. When glycogenesis occurs, glycogenolysis is inhibited, and vice versa. Impaired glycogen metabolism, characterized by abnormal glycogen accumulation, is associated with inherited metabolic disorders and is collectively known as glycogen storage diseases.