glycogen

Examples of glycogen in the following topics:

• Galactosemia and Glycogen Storage Disease

  • Glycogen storage disease (GSD, also glycogenosis and dextrinosis) is the result of defects in the processing of glycogen synthesis or breakdown within muscles, liver, and other cell types.
  • Overall, according to a study in British Columbia, approximately 2.3 children per 100,000 births (one in 43,000) have some form of glycogen storage disease.
  • There are 11 distinct diseases that are commonly considered to be glycogen storage diseases (some previously thought to be distinct have been reclassified).

• Absorptive State

  • During this sleep period, anabolic processes are busy building up stores of fats and glycogen that will be needed in the future to provide energy for the growing baby.
  • The glucose then travels to the blood or is converted to glycogen and fat (triglyceride) for energy storage.
  • The glycogen and fat will be stored in the liver and adipose tissue, respectively, as reserves for the post-absorptive state.
  • The remaining glucose is taken in for use by body cells or stored in skeletal muscle as glycogen.

• Insulin Secretion and Regulation of Glucagon

  • Glucose is stored in the liver in the form of the polysaccharide glycogen, which is a glucan.
  • Liver cells have glucagon receptors and when glucagon binds to the liver cells they convert glycogen into individual glucose molecules and release them into the bloodstream—this process is known as glycogenolysis.
  • It's main role is to promote the conversion of circulating glucose into glycogen via glycogenesis in the liver and muscle cells.

• Muscle Metabolism

  • The glucose for glycolysis can be provided by the blood supply, but is more often converted from glycogen in the muscle fibers.
  • If glycogen stores in the muscle fibers are expended, glucose can be created from fats and proteins.
  • Cellular respiration plays a key role in returning the muscles to normal after exercise, converting the excess pyruvate into ATP and regenerating the stores of ATP, phosphocreatine, and glycogen in the muscle that are required for more rapid contractions.

• Disease as Homeostatic Imbalance

  • The cells convert excess glucose to an insoluble substance called glycogen to prevent it from interfering with cellular metabolism.
  • Another hormone called glucagon performs the opposite function of insulin, causing cells to convert glycogen to glucose and stimulating new glucose production (gluconeogenesis) to raise blood sugar levels.

• Interactions of Hormones at Target Cells

  • Liver and muscle cells convert glucose to glycogen, for short-term storage, and adipose cells convert glucose to fat.
  • The glucose in the liver originates from the breakdown of glycogen.

• Mechanisms of Chemical Digestion

  • Carbohydrates are taken in mainly in the form of plant carbohydrate (amylose) and animal carbohydrate (glycogen) together with some sugars, mainly disaccharides.
  • Glycogen is a multi-branched starch with linkages at the 1:4 and 1:6 position.
  • This breaks amylose down into mainly disaccharides, and glycogen with its 1:6 linkages into polysaccharides .

• Adjustments of the Infant at Birth

  • Glycogen synthesis in the liver and muscle begins in the late second trimester of pregnancy, storage is completed in the third trimester.
  • Glycogen stores are maximal at term, but even then, the fetus only has enough glycogen available to meet energy needs for 8–10 hours, which can be depleted even more quickly if the demand is high.

• Metabolic Changes

  • These include: translocation of Glut-4 transporter to the plasma membrane and influx of glucose (3), glycogen synthesis (4), glycolysis (5) and fatty acid synthesis (6).

• The Liver and Gallbladder

  • It is the second-largest organ in the body, and is located on the right side of the abdomen.The liver plays a major role in metabolism and has a number of functions in the body, including glycogen storage, plasma protein synthesis, and drug detoxification.