WHAT IS GLYCOGENOLYSIS? - ANATOMY AND PHYSIOLOGY - 2024

The glycogenolysis, also called glycogenolysis, is the procedure through which degrades glycogen in the body, in order to produce a glucose quickly.

Glycogen is characterized by being an element located in the cytosol, which is the liquid that is part of cells. Through glycogen, the body is able to reserve energy from glucose.

Glycogen is located in almost all animal cells, and within the body it is located in the liver and skeletal muscles (those that are attached to the skeleton). The glycogen located in the muscles is more abundant than that located in the liver.

When there is a lot of glucose consumption, it accumulates in the body under the figure of glycogen.

In this way, a reserve of energy is generated that can be mobilized according to the needs of the body.

So when the body is carrying out a physically demanding activity, such as an intense exercise routine, the process of glycogenolysis occurs, to transport glucose to the muscles as quickly as possible.

The glycogenolysis process is also activated when the body is undergoing a fast, because it will also need energy sent quickly and directly to the muscles and the bloodstream, through the function of the liver.

As mentioned above, glycogen is present in almost all of the animal world. However, in the plant world a process of energy release is also generated.

This process typical of plants is not generated through glycogen, but through starch, which is responsible for reserving energy and releasing it, when necessary, in the form of glucose.

How is glycogenolysis generated?

Three enzymes (proteins produced by cells whose functions have to do with the regulation of chemical reactions in the body) participate in the glycogenolysis process.

The glycogenolysis process begins with glycogen, an element that constitutes the most important form of carbohydrate storage in animal organisms.

The first enzyme that intervenes is called glycogen phosphorylase, which generates glucose-1-phosphate through glycogen.

By means of a phosphorylation action, that is, the introduction of a phosphate group into the molecule, the enzyme glycogen phosphorylase is responsible for separating the glucose from the linear structure, until reaching the point where it reaches four residues of glucose.

At this point in the process, the second enzyme participates, which is the debranching enzyme. This enzyme breaks other bonds that are part of glycogen and generates a free glucose molecule.

Then, as a consequence of the glycogenolysis process, two molecules are generated: one of glucose-1-phosphate and the other of free glucose.

Glucose-1-phosphate mutates to glucose-6-phosphate, by the action of an enzyme called phosphoglucomutase.

Depending on the body's needs, glucose-6-phosphate can be converted to two molecules of adenosine triphosphate (ATP) through glycolysis.

It can also be converted into glucose, through the action of the enzyme glucose-6-phosphatase that can be found in the liver; once converted into glucose, it can be used in processes of other cells.

The glucose-6-phosphate molecules found in the liver can carry out this process of conversion to glucose through glucose-6-phosphatase.

However, if these molecules are found in the muscles, such a conversion is not possible, because the enzyme glucose-6-phosphatase is found only in the liver, not in the muscles.

Glycogenolysis Regulatory Hormones

When there are low levels of glucose in the blood, there are two hormones that act in the body by stimulating the appearance of the enzyme glycogen phosphorylase, which is the first to act on glycogen.

These two hormones are called glucagon and adrenaline. The glucagon hormone acts on the liver, and adrenaline acts on the skeletal muscles.

Both carry out different reactions that, finally, stimulate the breakdown of glycogen through the generation of the enzyme glycogen phosphorylase.

Importance of glycogenolysis

Through the process of glycogenolysis, the body is able to obtain glucose that is directed to both the liver and the muscles.

In the liver

When glycogenolysis occurs in the liver, glucose is released into the blood, a process associated with maintaining an accepted value for glycemia (blood sugar level).

This process is also very important in the transfer of glucose to the brain, since glucose is only able to get there through the bloodstream. The source of energy for the brain is the glucose it receives from the blood.

The supply of energy to the brain in the form of glucose will increase the ability to concentrate and it will work more efficiently, there will be less fatigue and more focus on the activity that is being carried out.

In the muscles

In the case of glycogenolysis that is generated in the muscular field, this is of vital importance because it allows the muscles to receive energy when the body is carrying out intense activity, for example, a very demanding routine of physical exercises.

So, glycogenolysis is the process through which it is possible to release energy quickly when the muscles need it. It is the way to use that energy reserved in the body in the form of glycogen.

The possibility of having an energy reservoir is essential for the body, and can only be achieved through glycogen, which stores glucose in cells and keeps it accessible for the moment when the body claims it.

A low energy reservoir translates directly into a low performance of the body's functionalities.

If a muscle does not receive enough energy during a time of intense exercise, it can become fatigued and seriously injured.

For this reason, a diet rich in carbohydrates is recommended for athletes, so that glucose reserves, under the figure of glycogen, are abundant and can respond to the demands of constant and high-intensity training.

References

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