Glycogen Metabolism

Glycogen is a very lage branched polymer that readily mobilized storage form of glucose. Our body needs energy. It is accumulated in response to insulin and broken down into glucose

Structure and Function

• The main store of glycogen in body are found in skeletal muscle and liver.
• The function of muscle glycogen is to serve as a fuel reserve for the synthesis of ATP during contraction.
• The liver glycogen is to maintain the blood glucose concentration, particularly during the early stage of fasting.
• Structure of glycogen is a branched-chain polysaccharide made exclusively from α-D-glucose.
• Glycogen is synthesized from glucose by the pathway of glycogenesis. It is broken down by a separate pathway, glycogenolysis.
• Cyclic AMP integrates the regulation of glycogenolysis and glycogenesis by promoting the simultaneous activation of phosphorylase and inhibition of glycogen synthase. Insulin acts reciprocally by inhibiting glycogenolysis and stimulating glycogenesis. 

Glycogenesis : formation of glycogen from glucose.

Glycogenolysis : breakdown of glycogen to glycose.