Biochemistry

transformation of monomers', glucose is obtained from galactose and fructose with the participation of enzymes isomerase. In the liver, under the action of the enzyme phosphorylase, glycogen is synthesized and accumulates. If necessary, it is mobilized and split to free glucose. In the human body glycogen stock is 350 g, with 250 g contained in the muscles. Gluconeogenesis reaction is also proceeds in the liver: glucose is formed from non-carbohydrates (lactic acid, glycerol, amino acids). From the liver, glucose is delivered to various organs, where it is used by cells as a source of energy as needed. In the kidneys of a healthy person, glucose is completely reabsorbed and returns back to the blood. 11.2 REGULATION OF CARBOHYDRATE METABOLISM AND ITS DISORDER The level of glucose in the blood of healthy people is constant, it reflects the state of carbohydrate metabolism in general and glucose in particular. Normally, blood contains 3.33-5.55 mmol/1 (~ 4- 6 units) of carbohydrates. Blood monosaccharides are mainly used for the energy needs of the body (70%), some of them are involved in the biosynthesis of lipids, antibodies, mucopolysaccharides, i.e , it performs a plastic function. Glucose has the most importance in the human body. This is due to the its high, as compared with other monosaccharides, content in food products and in the body, as well as with greater activity of cellular enzymes that catalyze its transformation. In addition, the liver actively processes the conversion of various monosaccharides into glucose, and only it can be stored in the form of glycogen, which, when breaking down, provides for the needs of the body in this carbohydrate. Various disorders of carbohydrate metabolism are manifested primarily by changes in blood glucose, and the regulation of this type of metabolism can be viewed as the regulation of blood glucose level. Carbohydrate metabolism in general and the amount of glucose in the blood, in particular, are regulated by the nervous system and the endocrine glands. A natural irritant is a decrease of glucose in blood (hypoglycemia), occurring in cases where the intervals between regular meals exceed 5-6 hours. Glucose-depleted blood enters the brain, causing reflex stimulation of the metabolic centers of the hypothalamus and the medulla. In response, impulses arise that stimulate the breakdown of liver glycogen to glucose and restore its blood level to normal. An important place in the regulation of carbohydrate metabolism belongs to the hormone of the pancreas - insulin, which is formed in fl-cells of the insular tissue of the pancreas. Insulin reduces the level of glucose in the blood by actively 213