ANDROGENS

From Big Medical Encyclopedia

ANDROGENS (Greek anzr, andros - the man and genesis — an origin) — the substances having activity of male sex hormone — testosterone. Several tens of natural compounds having to an androgeshsha of property are known. Natural androgenic hormones of sec. retire seed plants and bark of adrenal glands of the person and animals. Represent derivatives of an androstan: testosterone (андрост-4-ен-17β-ол-3-он, Cl 9 H 28 O 2  ; pier. weight 288,41), androstendion (androst-4-en-3,17-dion), 11β-оксианд rostendion (андрост-4-ен-11β-окси-3,17-дион), degidroepiandrosteron (андрост-5-ен-3β-ол-17-он), adrenosteron (androst-4-en-3, 11, 17-trion) and androsterone (5α-андростан-3β-ол-17-он). The most active androgenic hormone — testosterone (see) it was for the first time allocated from seed plants of a bull in 1935. Dihydrotestosterone is even more active its metabolite.

Biosynthesis of androgens and their turning into organism

adrenosteron
androsterone
androstendion
degidroepiandrosteron
testosterone
dihydrotestosterone

Biosynthesis of testosterone is carried out in intersticial fabric of seed plants by cells of Leydiga. In the blood flowing from seed plants except testosterone, androsterone, androstendion and degidroepiandrosteron are found in small amounts (fig.). Two last And., and also sulfate of a degidroepiandrosteron, 11β-оксиан-дростендион and adrenosteron cosecrete bark of adrenal glands of the person.

Biosynthesis And. in closed glands includes a number of consecutive enzymatic transformations of cholesterol. Cholesterol as a result of reactions of a hydroxylation at 20 both 22 carbon atoms and the subsequent eliminating of a 6-carbon side chain with the participation of mitochondrial enzyme of desmolase turns in pregnenolon. It is established that further transformation of a pregnenolon into testosterone can go to fabrics of seed plants on two ways: 1) through progesterone, 17α-оксипрогестерон and androstendion; 2) through 17-oksipregnenolon, degidroepiandrosteron and androyetendion. The enzymes catalyzing these reactions are localized in microsomes. The reaction limiting the Speed of education And. in seed plants, reaction 20α-гидроксилирования cholesterol is. Luteinizing hormone of a hypophysis — the main physiological regulator of secretion exerts impact on this stage of process And. seed plants (see. Luteinizing hormone ).

In an organism of animals And. are formed not only in closed glands, but also in other bodies as a result of metabolism of corticosteroids and androgenic hormones. So, in a liver there is a recovery of a ring of a molecule of Ampere-second formation of androsterone, an etiokholaio-bosom and androstan-3,17-diols. Androgenic connections with oxygen function at S-11, such as 11-oksi-and 11 ketoandrosterone and 11-oksi-and 11-ketoetikholanolon, are formed in a small amount at degradation of corticosteroids, a hydrocortisone and cortisone. Metabolites, behind a small exception, weak And., but some of them are characterized also by other biological properties. So, androsterone possesses gipokholesterinemichesky, and etiocholanolone — the pyrogenic action. Androstenolona, on a nek-eye to tests, so strong And., as well as testosterone.

And., having ketogroup at the 17th carbon atom, combine a concept 17 of ketosteroids.

In a liver And. connect To glucuronic or sulfuric acids and in the form of glucuronides or sulfates are excreted with urine. And. contain in blood partially in the form of lipoproteids from where are easily taken at extraction by organic solvents, partially in the form of free glyukuronozid and sulfates.

Physiological action of androgens

Biological effect And. the hl is shown. obr. in their influence on development of secondary sexual characteristics, such as character of pilosis, a timbre of a voice, distribution of fat, development of muscles, etc. Functions of all departments of a sexual path and the related glands are also regulated And. They determine growth of a scrotum, seed bubbles, a prostate, penis, bulbourethral glands.

Essential value A. have in regulation of secretion of gonadotropic hormones a hypophysis and influence formation of a floor a hypothalamus. Besides, And. influence many biochemical processes in an organism which are not connected with the characteristic of a floor. So, And. cause anabolic effect (see. Anabolic steroids ), change exchange of carbohydrates, lipids, cholesterol, electrolytes. Insufficient secretion And. leads to development hypogonadism (see), excessive — various forms hypergenitalism (see).

Mechanism of action And. in cells of target organs it is connected with regulation of processes of biosynthesis of proteins-enzymes at the level of genes. Testosterone coming from blood to cells communicates specific proteins receptors, is exposed to enzymatic transformation with formation of an active form A. — the dihydrotestosterone stimulating process of DNA replication, transfer of genetic information from DNA on RNA and biosynthesis of proteins on ribosomes. Period of action And. very short, they are quickly brought from an organism.

Biological activity And. determine by growth of a crest at the castrated roosters or at young cockerels, by development of a prostate and seed bubbles in the castrated males of rats and mice.

Methods of definition

Methods of determination of speed of secretion and speed of products And. are closely connected with development of methods of determination of their content in blood and urine and their allocation in pure form. Determination of content of testosterone in urine at people is carried out for clarification of function of seed plants. Determination of total quantity of 17 ketosteroids in urine allows to judge approximately function of bark of adrenal glands, and individual 17 ketosteroids of urine — to detail a functional condition of adrenal glands and gonads. Isotope dilution methods and competitive linkng of steroids with proteins give the chance to determine the content of testosterone and others And. in a blood plasma. Excretion of testosterone with urine at men at the age of 20 — 40 years makes apprx. 70, women have 8 mkg a day. Children up to 3 years have an allocation of 17 ketosteroids with urine insignificant. Further with age it increases and reaches a maximum by 20 — 35 years, reaching 6 — 15 mg a day at women and 15 — 25 mg a day is at men, then again decreases and remains at a low level until the end of life.

For use in medical practice And. receive in the synthetic way and appoint to men at treatment of an eunuchoidism, inborn underdevelopment of gonads, at the vascular and nervous breakdowns connected with a climacteric and also at diseases of other hemadens causing disturbances of functions of gonads (an acromegalia, an addisonova a disease, adiposogenital dystrophy, etc.).

To women And. appoint at dysfunctional uterine bleedings, climacteric frustration, at mastopathies, at malignant tumors of a mammary gland.

And. it is also possible to appoint at various morbid conditions which are followed by the strengthened disintegration of proteins (the period of reconvalescence after serious infectious diseases, an injury, etc.); disbolism — osteoporosis (see. Anabolic steroids , Hormonal therapy ).


Bibliography: Vartapetov B. A. and Demchenko A. N. Klimaks at men, Kiev, 1965, bibliogr.; Zavadovsky M. M. Floor and development of its signs, M., 1922; Klyucharev B. V. Experimental new growths of a prostate and their hormonal therapy, L., 1954; Nazarov I. N. and Bergelson L. D. Chemistry of steroid hormones, page 10 7, M., 19 55, bibliogr.; Samyuele L. T. Biosynthesis of androgens, Works of the 5th Mezhdunarodn. biochemical kongr., Symposium 7, page 363, M., 1962, bibliogr.; Modern methods of definition of steroid hormones in biological liquids, under the editorship of N. A. Yudayev, M., 1968; Starkova N. T. Fundamentals of clinical andrology, M., 1973; Fizer L. and Fizer M. Steroids, the lane with English, page 520, M., 1964; Heftman E. Biochemistry of steroids of the lane with English, page 114, M., 1972; Androgens in normal and pathological conditions, ed. by A. Vermeulen, Amsterdam a. o., 1966, bibliogr.; Dorfman R. I. Androgens, Meth. Hormone Res., v. 5, p. 235, 1966; Dorfman R. I. a. Shipley R. A. Androgens, N. Y., 1956; Gonads, ed. by K. W. McKerns, N. Y., 1969; Robel P., Milgrom E. Baulieu E. E. Les androgènes surrénaliens (Biosynthèse, transport, métabolisme et pathologie), Actualités endocrinol., ser. 12, p. 5, 1971; Snipes C. A., Becker W. G. a. Migeon C. J. The effect of age on the in vitro metabolism of androgen by guinea pig testis, Steroids, v. 6, p. 771, 1965; Testosterone, ed. by J. Tamm, Stuttgart, 1968.

M. A. Krekhova.

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