GLUCOGEN METABOLISM
* Importance of glycogen. Glycogen is stored together with its enzymes in glycogen granules, which are different depending on whether we are in the liver and in the muscle. In the liver, glycogen weighs 109 Da, while in the muscle, its weight is 2x107.
In the liver, we find 65 g / Kg, while in the muscle there is only 14g / Kg. In addition, in the muscle, this value does not change during fasting, since glycogen is necessary for muscle contraction to occur. On the contrary, the amount of glycogen in the liver does change, to the point that, 24 hours after a fast, it has almost completely disappeared.
Glycogen is a branched polymer of glucose, linked by a-1,4 and a-1,6 bonds.
reducing end, and therefore degradation begins at the non-reducing end, that is, the left end.
Its main function is to act as a hydrate reserve source (glucose) for rapid mobilization. Glycogen is present in all tissues, but mainly in the muscle and liver. It is located in the cytosol of cells, in the form of granules, and associated with enzymes of its metabolism.
Blood glucose levels should be around optimal values. Therefore, when glucose levels rise, it is stored in the form of glycogen to prevent homeostasis and to be easier to mobilize.
Glycogen in the liver has a reserve function, while in the muscle it is used to produce ATP quickly that allows contraction, both under aerobic and anaerobic conditions.
while liver glycogen begins to disappear after a period of 12 to 24 hours.
The breakdown of glycogen to glucose is glycogenolysis, while the transition from glucose to glycogen is glycogenolysis. Glycogen functions in the muscle and liver. In the muscle, glycogen passes into
Glucogeno
Glucogenogenesis
Glucogenolisis
Glucosa
1
glucose 1-phosphate, which is transformed into glucose 6-phosphate, which will produce ATP, CO2 and lactate through glycolysis.
phosphtase releases the phosphate group at position 6 of glucose, allowing glucose to be released into the blood.
Musculo
Higado
GLUCOGENO
Glucosa-1-p
Glucosa-6- sfatasa
Glucosa
Glucosa
If we measure the content of liver glycogen throughout the day, we observe that. at times of fasting, the glycogen content decreases and, when eating food, increases.
Bam
Mediodia
4 om
8pm
Medianoche
The main functions of glycogen in the liver and in the muscle are:
HEPATIC GLUCOGEN
MUSCLE GLUCOGEN Reserve fuel for muscle contraction
PRINCIPAL FUNCTION OTHER FUNCTIONS
Maintenance of blood glucose concentration Used as fuel for any fabric
10% of the weight of the liver is glycogen. Only lasts 12-24 hours during fasting
1-2% of the weight of the muscle, but having a lot of muscle mass is twice that in the liver Epinephrine stimulates glycogenolysis, while insulin stimulates synthesis
DEPOSITS
Glucagon and epinephrine stimulate glycogenolysis, while insulin stimulates synthesis
HORMONAL CONTROL
2
* Glycogen catabolism. Glycogenolysis.Glycogenolysis is a glycogen pathway that gives rise to glucose 1-phosphate molecules, thanks to the action of a glycogen phosphorylase. Glucose 1-phosphate passes to glucose 6-phosphate through a hexokinase or glucokinase, depending on th