Growth hormone: chemical nature, biological action, pathology

Hormones are bioactive substances that are synthesized by the endocrine glands and are secreted directly into the blood, liquor, or lymph. Hormones show high biological activity in scanty doses of 10-3 and even 10-6 mg. They show a short-term effect and are quickly destroyed.

Properties of hormones.

For most hormones, the molecular structure is deciphered. Many of them were obtained in pure form (folliculin, insulin); Some of them are synthesized (insulin, adrenaline, cortisone). The activity of the endocrine glands is controlled by the nervous system. In turn, these glands affect the activity of the nervous system. Hormones affect the metabolism of proteins, carbohydrates, nucleic acids, lipids, minerals.

Growth hormone (somatotropin, growth hormone, STH) was isolated from the extracts of the adenohypophysis by Evans and Long in 1921. The pituitary gland is one of the most important glands of internal secretion. Together with the hypothalamus forms a single morphophysiological system that regulates different aspects of the metabolism of substances. The hormone has a protein nature and an oligomeric structure. Molecular weight 23000-46000 Yes. The growth hormone consists of two polypeptide bonds that contain 191 amino acid residues.

A characteristic feature of growth hormone is that it shows specific specificity. It should be said that for the human biologically active is only the somatotropic hormone of primates.

With hypoecretion of somatotropin, there are disturbances of some metabolic processes in the body, namely, anabolic processes and growth processes. With excessive release of the hormone (hyperfunction of the gland) at a young age, before puberty and until the formation of bone tissue is complete, there is an increased growth of the human body, which leads to gigantism. The growth of individuals in this case can be from 2 to 2.7 m. Excessive release of STH in adulthood leads to the development of acromegaly. This disease occurs with hyperplasia and adenomas of the pituitary gland. Symptoms of the disease are a disproportionate growth of individual parts of the body, excessive growth of limb bones, heads, proliferation of soft tissues - nose, lips, tongue, chin. There is an increase in internal organs, the hypertrophy of some endocrine glands is recorded.

With insufficient synthesis of growth hormone (hyposelection) at a young age, dwarfism ( Nanism) is observed . The growth in this case does not exceed 90-120 cm, there are no secondary sexual characteristics. Pituitary dwarfs have a relatively proportionate body structure, slightly enlarged head. In mental development, they do not differ from ordinary people.

The growth hormone affects the anabolic processes: it activates the biosynthesis of proteins, nucleic acids, increases the level of glucose in the blood (diabetic effect), stimulates reticulocytosis, chondro- and osteogenesis.

The human body synthesizes many bioactive substances that provide us with pleasant sensations (euphoria, good mood, pleasure). In biochemistry, these substances are called neurotransmitters, they are responsible for the transmission of nerve impulses. There is an opinion that serotonin, endorphins and dopamine are hormones of pleasure. Serotonin is a hormone of good mood. When ingested, it increases motor activity, improves mood. Deficiency of serotonin can lead to depression. Endorphins are synthesized in the body in stressful situations, to reduce pain. Linking to opiate receptors, they suppress pain, causing euphoria. Dopamine is often called a pleasure hormone. The higher the concentration of this compound in the blood, the brighter the sensation.