Test questions

1. Give the classification of hormones on their chemical nature.

2. What is the mechanism of hormones action?

3. Describe the pituitary hormones and their effects on metabolism.

4. Describe the hormones of the pancreas.

5. What is the biological role of thyroid hormones?

6. What structure are the hormones of the adrenal medulla? What is their role in metabolism?

7. Give a description of the biological role of parathyroid hormone.

8. What is the biological role and structure of the adrenal cortex hormones?

9. What functions are performed by sex hormones in the organism? What is their chemical nature?

5. Metabolic processes interaction

In the organism

Metabolism in the human organism occurs as one whole system, in close interaction and interdependence of individual components of its processes. Even the first stage of metabolism – the digestion of food in the gastrointestinal tract – is at the same time the degradation of proteins, lipids and carbohydrates. Further conversion of proteins, lipids and carbohydrates in the tissues in the processes of intermediate metabolism is so intimately linked that to the whole organism, for example, , isolated carbohydrate metabolism is an abstraction for the whole body. The specific relationship between various forms of metabolism has been discovered. It is expressed in the fact that the individual structural elements of proteins, lipids and carbohydrates can be converted into each other after appropriate chemical conversions. For example, the amino acids are used for the synthesis of carbohydrates and vice versa.

Protein and carbohydrate metabolisms interconnection

In the cause of carbohydrate degradation in tissues, pyruvic acid is formed as an intermediate product. In the process of further transformations it can produce oxaloacetate and α-keto-glutaric acid. These three α-keto-glutaric acids could be aminated and give correspondingly alanine, aspartic acid and glutamic acid. Such a conversion of carbohydrate metabolism products in the amino acid indicates a direct link between metabolism of carbohydrates and proteins. The formation of other amino acids from the products of carbohydrate metabolism is also considered an established fact. For example, the amino acid serine is formed by transamination hydroxipyruvic acid, which in turn is formed from phosphoglyceric acid. Cysteine, and, therefore, cystine, is formed from homocysteine and serine. The amino acid glycine is formed by serine splitting. Proline is formed from glutamic acid, which is formed, in turn, from the products of carbohydrate metabolism through the TCA cycle. Oxidized in the organism, proline becomes hydroxyproline.

The relationship between protein and carbohydrate metabolism clearly illustrates the structure of complex proteins and nucleoproteins chromoproteins in the construction of which the intermediate products of carbohydrate metabolism are involved.

Between the transformation of carbohydrate metabolism products in the products of protein metabolism there is a feedback of a similar nature – the synthesis of carbohydrates from proteins. This is proved by new formation of carbohydrates from proteins by gluconeogenesis and normal development of the organism at one-direction use of proteins, ie the exclusion of carbohydrates and lipids from the diet. The relationship between protein and carbohydrate metabolism is proved with the diabetes mellitus pathogenesis. The human organism in diabetes mellitus loses the ability to use glucose properly and deposit it in the tissues in the form of glycogen. Introduced with the food protein is largely released in the form of glucose from the patient with diabetes mellitus. More than 50% (and sometimes up to 80%) injected into the organism protein is converted into glucose. The starting substrate for gluconeogenesis is amino acids, the degradation of which pyruvic acid is formed by the one way or another.