Hormones are bioactive substances that are synthesized by the endocrine glands and secreted directly into the blood, cerebrospinal fluid or lymph. Hormones exhibit high biological activity in scanty doses of 10-3 and even 10-6 mg. They exhibit short-term effects and are rapidly destroyed.
The properties of hormones.
For most hormones, the molecular structure has been deciphered. Many of them are 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 extracts of the adenohypophysis by Evans and Long in 1921. The pituitary gland is one of the most important endocrine glands. Together with the hypothalamus, it forms a single morphophysiological system that regulates different aspects of the metabolism of substances. The hormone has a protein nature and oligomeric structure. Molecular Weight of 23000-46000 Yes. Growth hormone consists of two polypeptide bonds that contain 191 amino acid residues.
A characteristic feature of growth hormone is that it exhibits species specificity. It should be said that for humans, only the somatotropic hormone of primates is biologically active.
With somatotropin hyposecretion, disorders of some metabolic processes in the body occur, namely anabolic processes and growth processes. With excessive secretion of the hormone (gland hyperfunction) at a young age, before the onset of puberty and before the completion of bone formation, 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 pituitary adenomas. Symptoms of the disease are disproportionate overgrowth of individual parts of the body, excessive growth of bones of the limbs, head, proliferation of soft tissues - nose, lips, tongue, chin. An increase in internal organs is observed, hypertrophy of some endocrine glands is recorded.
With insufficient synthesis of growth hormone (hyposecretion) at a young age, dwarfism (dwarfism) is observed. The growth does not exceed 90-120 cm, there are no secondary sexual characteristics. Pituitary dwarfs have a relatively proportional body structure, a slightly enlarged head. In mental development, they do not differ from ordinary people.
Growth hormone affects 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 a pleasant sensation (euphoria, good mood, pleasure). In biochemistry, these substances are called neurotransmitters, they are responsible for the transmission of nerve impulses. It is believed that serotonin, endorphins and dopamine are hormones of pleasure. Serotonin is a hormone of good mood. When it enters the bloodstream, it increases motor activity, improves mood. Serotonin deficiency can lead to depression. Endorphins are synthesized in the body in stressful situations, to reduce pain. Contacting opiate receptors, they suppress pain, causing euphoria. Dopamine is often called the hormone of pleasure. The higher the concentration of the specified compound in the blood, the brighter the sensation.