From Big Medical Encyclopedia

SOMATOTROPIC HORMONE (Greek soma, somatos body + tropos direction; hormone[s], STG, synonym; Somatotropinum, growth hormone) — the anterior pituitary hormone, participates in regulation of all types of a metabolism in a human body and animals, the main effect of hormone consists in anabolic influence on protein metabolism, in stimulation of growth of a skeleton and increase in the sizes of a body. This year causes increase in synthesis of protein in all fabrics and internals, under its influence synthesis of DNA and RNA amplifies, total number of cells increases, activity of nek-ry enzymes increases. Stimulating growth of bones in length at the expense of an epiphyseal cartilage, This year causes increase in length of a body of immature animals and the person. Under influence This year as a result of the periosteal growth of a bone increase also in width. Supersecretion This year at people with ended fiziol. growth (see) is the reason of a serious illness — acromegalias (see). At patol. hyperproductions This year at children's and youthful age giantism develops (see), to-ry is age option of an acromegalia. Insufficiency of somatotropic hormone and a number of triple hormones (see) causes a sharp growth inhibition, differentiations of a skeleton and other fabrics and bodies — a so-called pituitary nanism (see. Dwarfism ).

This year it is developed in somatotrofa — the eosinophial (acidophilic) cells of a front share of a hypophysis (see) making up to 35% of total number of secretory cells of a front share. This year the person is represented by the polypeptide constructed of 191 amino-acid rests (trailer amino acids — the remains of phenylalanine, the remains of cysteine in 53 — 165 and 182 — 189 provisions are connected disulfide, S — S-, bonds), apprx. a half of a polypeptide chain is curtailed in the form of an alpha spiral.

Pier. weight (weight) This year person 21 500, isoelectric point (see) is at pH 4,9. Considerable specific specificity is characteristic of a chemical structure, immunological and biological properties This year. So, the sequence of the amino-acid remains in a polypeptide chain This year of the person, sheep and cattle matches only for 65%. The reason of specific specificity consists not only in variations of a chemical structure of the hormone This year, but also in distinctions in the fabric receptors perceiving its action. Somatotropic hormone of animals is inactive concerning the person, but This year shows the person specific biol. activity at introduction to various animals, including and rats.

Secretion a hypophysis is This year under control hypothalamus (see). Hypothalamic neurohormones (see) — somatoliberin and somatostatin (see) through portal circulatory system of a hypophysis reach its front share and regulate the speed of synthesis and release This year. Secretion increases during the nek-ry periods of a dream, at stresses, an exercise stress, decrease in concentration of glucose in blood and starvation This year. Stimulate secretion This year insulin, amino acids (arginine, a leucine, tryptophane, etc.), beta and adrenergic blockers (inderal, ana-prilin), dofaminergichesky agonists (L-DOFA, Apomorphinum, Parlodelum), and - adrenergic agonists (noradrenaline, a clonidine), endogenous opiates (see. Opiates endogenous ), and also glucagon, vasopressin, serotonin, estrogen, androgens, anabolic steroids. Reduction of content of somatotropic hormone in blood is observed at a hyperglycemia, a gross obesity, a hypothyroidism, various defeats of hypothalamic or pituitary area. Reduce secretion This year somatostatin, antagonists of serotonin (cyproheptadine, metisergid), dofaminergichesky antagonists (a haloperidol, Chlorpromazinum), p-adrenergic agonists (Isoproterenolum), and - adrenergic antagonists (phentolamine), morphine.

Specific action This year on lipometabolism (see) consists in passing insulinopodobny effect, to-ry it is shown by stimulation of processes of a lipogenesis. However then under influence there is the strengthening of a lipolysis to increase in mobilization of fat from fat depos This year (see. Lipotropic factors of a hypophysis) leading to increase in contents in a blood plasma of free fatty acids (see), to their intensive oxidation and, in case of insufficiency of insulin, to increase in content in blood of ketone bodies (see).

(See) somatotropic hormone also has short-term insulinopodobny effect on carbohydrate metabolism that is shown by increase in absorption and utilization of glucose (see) and insignificant decrease in its content in blood. At constant supersecretion This year use of glucose fatty and muscular tissue decreases, and intensity of a gluconeogenesis in a liver increases. Besides, This year stimulates formation of a glucagon (see) in a pancreas also increases activity of the enzymes destroying insulin. Thus, action on carbohydrate metabolism has This year diabetogenic character.

Peripheral action begins with interaction of hormone with the corresponding receptors located on cytoplasmic membranes of target cells This year. The specific places of binding which are characterized by high affinity to This year are found on cytoplasmic membranes of hepatocytes and leukocytes. The major property — ability to stimulate growth of a skeleton and other growth processes — is substantially caused This year by activation of products of somatomedins (see) — the insulinopodobny growth factors which are carrying out a role of intermediaries biol. effects of somatotropic hormone.

For biol. definitions most often apply This year the tests based on ability of this hormone at introduction to gipofizektomirovan-ny rats to stimulate increase in body weight, to increase width of an epiphyseal cartilage of a tibial bone (the so-called tibia-test), to strengthen inclusion of marked sulfate in cartilaginous tissue or marked proline in skin. Standardization biol. activities of drugs carry out by its comparison to activity of the international standard of hormone This year. Activity is expressed in the conventional units of action (UA) This year.

Content in blood serum is determined This year by a radio immunological method (see). Concentration in blood serum of healthy people makes This year 3,81 ± 0,2 ng/ml, at an acromegalia 20,51 ± 2,06 ng/ml, at a pituitary nanism 1,34 ± 0,29 ng/ml.

In the late seventies for 20 century it was offered biol. a method of synthesis This year the person with use of E. coli. By methods of genetic engineering the gene responsible for synthesis This year at the person, was implemented in a plasmid of E. coli, edges as a result of it were got by ability to synthesize This year the person. Such «bacterial»

differs from natural hormone only in existence of the additional rest of methionine on N-koh-tse polypeptide chains This year, but at biol. testing this hormone shows the activity inherent natural the person This year. Drugs of the person «bacterial» This year pass a wedge, tests.

In a wedge, practice for treatment of a pituitary nanism as medicine apply Somatotropinum (person) to injections (Somatotropinum humanum pro injectionibus). Drug represents the sterile lyophilized powder of white color with a cream shade received from extracts of hypophyses of the died people water soluble and solutions of novocaine. Activity of drug is defined biol. by method. 1 mg of drug contains 4 PIECES This year. Drug just before use is dissolved in 2 ml of water for injections or 0,25 — 0,5% of solution of novocaine and enter intramusculary 2 — 4 PIECES 3 times a week. Usually treatment continues 2 years and more. At the patients keeping sensitivity to drug, duration of treatment increases. It must be kept in mind that at long use This year in an organism antibodies to hormone in this connection efficiency of the carried-out therapy decreases therefore treatment is recommended to carry out by courses (3 — 4 courses a year lasting 2 months with two-month breaks) are formed.

At use of drug allergic reactions are sometimes possible This year (skin rash, an itch, etc.). At permanent side reactions drug is cancelled. Treatment is absolutely contraindicated at malignant new growths This year.

Form of release: in hermetically the corked bottles on 2 or 4 PIECES. Store in the dry place at a temperature not over 10 °, solution of drug can be stored at t ° 5 no more 48th hour.

Bibliography: Balabolkin M. I. Secretion of a growth hormone is normal also of pathology, page 172, M., 1978; Biochemistry of hormones and hormonal regulation, under the editorship of N. A. Yudayev, page 63, M., 1976; Damask steels A. And., Osipova T. A. and Pankov Yu. A. The hydrophobic peptide from a tryptic hydrolyzate of a somatotro-shtn of a cachalot having growth activity, Probl. endocrinins., t. 26, No. 6, page 54, 1980; N. A Mark. Pituitary nanism, M., 1975; N. A. Mark, etc. Experience of a clinical use of domestic drug of Somatotropinum of the person, Message 1. Dynamics of physical development, Probl. endocrinins., t. 24, No. 3, page 40, 1978; L and-shene D. G. Effektivnost of domestic Somatotropinum of the person at treatment of a gipotalamo-pituitary nanism, in the same place, t. 28, No. 3, page 39, 1982; Punks Yu. A. Rol of proteoliticheeky enzymes in some stages of biological effect of somatotropic hormone, Vestn. USSR Academy of Medical Sciences, Kya 9, page 38, 1982; Yuda-e in N. A. and d r, the Characteristic of a giro-mobilizuyushego of effect of the synthetic tetradecapeptide corresponding to the amino-acid sequence of 31 — 44 Somatotropinums of the person, Biochemistry, t. 44, century 10, page 1779, 1979; In of wasps of a s H. and. lake of Simultaneous translation of growth hormone and prolactin messenger RNA from rat pituitary tumor cells, FEBS Letters, v. 70, p. 175, 1976; Insulins, growth hormone, and recombinant DNA technology, ed. by J. L. Gueriguian, p. 117, N. Y., 1981; Polypeptide hormones, ed. by R. F. Beers a. E. G. Bassett, p. 281, N. Y., 1980.

M. I. Balabolkin.