Where is glycogen broken down and released?

Following secretion, glucagon travels to the liver, where it stimulates glycogenolysis. The vast majority of glucose that is released from glycogen comes from glucose-1-phosphate, which is formed when the enzyme glycogen phosphorylase catalyzes the breakdown of the glycogen polymer.

What tissues can store glycogen?

The two major sites of glycogen storage are the liver and skeletal muscle. The concentration of glycogen is higher in the liver than in muscle (10% versus 2% by weight), but more glycogen is stored in skeletal muscle overall because of its much greater mass.

How is glycogen released?

In these situations, when the body feels extra glucose is needed in the blood, the pancreas will release the hormone glucagon which triggers the conversion of glycogen into glucose for release into the bloodstream.

Does muscle tissue store glycogen?

Glycogen is the storage form of carbohydrates in mammals. In humans the majority of glycogen is stored in skeletal muscles (∼500 g) and the liver (∼100 g). Food is supplied in larger meals, but the blood glucose concentration has to be kept within narrow limits to survive and stay healthy.

How is glycogen extracted from a frozen liver?

While past structural studies have extracted glycogen from fresh or frozen tissue using a cold-water, sucrose-gradient centrifugation technique, a method for the extraction of glycogen from formalin-fixed liver would allow the analysis of glycogen from human tissues that are routinely collected in pathology laboratories.

Which is the best technique for glycogen extraction?

The formalin extraction technique, when combined with a protease treatment, resulted in higher yields (but lower purities) of glycogen with size distributions similar to the sucrose-gradient centrifugation technique.

Why does glycogen interfere with silica column purification?

Rather than being helpful, the glycogen content in tissue samples can interfere with silica column based purification. Basically, in a tissue preparation, you have tons of RNA, high guanidine salts, and then what do you do before binding the RNA or DNA to the column?

What should be the final concentration of glycogen?

For cartilage or heart tissue, go with the normal 33% final concentration (adding 0.5 volumes of 100% ethanol) but for skeletal muscle, which contains glycogen, try reducing it to 25%. I know this sounds like a lot of tinkering around with your precious samples.