17-OKSIKORTIKOSTEROIDY

From Big Medical Encyclopedia

17-OKSIKORTIKOSTEROIDY (17-OKC) — the steroid hormones which are formed in cortical substance of adrenal glands and their metabolites which are contained in blood and urine of the person and animals. Establishment of contents 17-OKC in blood, especially before and after loading of AKTG, and also measurement of excretion 17-OKC with urine is allowed to reveal funkts, it is normal of feature of secretion of hormones also at pathology adrenal glands (see), and also funkts, a condition of adrenal glands at various fiziol, and patol, impacts on a human body. By the chemical nature (fig. 1) 17-OKC represent neutral C 21 - the steroids having hydroxylic (OH-) group at the 17th and hydroxylic or carbonyl (CO-) group at the 20th carbon atoms (see. Corticosteroids ).

Fig. 1. Structure of a molecule 17 of oxycorticosteroids (elementary diagram).

The main representatives 17-OKC are hormones — hydrocortisone (see), cortisone (see) and 17-oxy-11-cortexone (17 - alpha oxycortexonum, korteksolon, connection S of Reykhstein) and products of their metabolism: A 5 alpha and 5th beta isomers 3-keto-recovered on a ring and 3-oxyderivative (digidro-and tetrahydroderivatives of hormones), and also the derivatives of these metabolites recovered on a side chain in 20 alpha and 20 beta provisions — cortols and kortolona.

Blood contains hl. obr. not changed hormones, with urine are generally removed their metabolites.

Fig. 2. Structure of a side chain of 17 oxycorticosteroids; and, in — the structure of a side chain characteristic of 17-ketogenic steroids; — a structure of a side chain of chromogens of Silber — Porter.

In fig. 2 the options of a structure of a side chain typical for 17-OKC are shown. In group 17-OKC distinguish subgroups of 17-ketogenic steroids (fig. 2, and, c) and Silber's chromogens — Porter (fig. 2, d).

The main hormones produced by cortical substance of adrenal glands of the person belong to Silber's chromogens — Porter: a hydrocortisone, a cortisone and 17-oxy-11-cortexone, and also their recovered on a ring And metabolites.

Content in biol, liquids of the general 17-OKC can be quantitatively determined by the Appl-bi method — Norimbersky. The method consists of recovery of ketogroups in a steroid borgidridy sodium and the subsequent oxidation vismutaty sodium. These chemical reactions are resulted by eliminating of a side chain in a molecule of a steroid with education 17 ketosteroids. Quantity of formed 17 ketosteroids (see) define by means of Tsimmermann's reaction based on condensation of 17 ketosteroids from m dinitrobenzene in alkaline condition with formation of connections with violet or red-violet coloring (a maximum of absorption at 520 nanometers). 17-Ketogennye steroids can be oxidized vismutaty sodium with formation of 17 ketosteroids without preliminary recovery. They can be quantitatively defined by the offered Norimbersky (J. To. Norymberski) method (see. Norimbersky method ). R. H. Silber's chromogens — Porter (17-OKC, having a dioksiatsetono-vy side chain) quantitatively determine by reaction with phenylhydrazine. For the first time this method was developed for blood in 1950 and for urine — in 1954 by R. H. Silber and Porter (S. S. Porter) and received the name of a method of R. H. Silber — Porter (see. Silbera — Porter methods ). Later modifications of these methods were offered, among to-rykh the greatest use found for blood — the method offered by N. A. Yudayev and Yu. A. Pankov (1958) and for urine — the method offered M. A. Krekhova (1960).

Establishment of content in blood or in daily amount of urine of chromogens of Silber — Porter has the greatest value during the definition funkts, conditions of adrenal glands of the person. Speaking about definition 17-OKC, most often mean determination not of the general content 17-OKC, but only contents of chromogens of Silber — Porter. Keeping of certain representatives of this group 17-OKC is defined only after their chromatographic fractionation on a thin coat of silica gel (see. Chromatography ).

Healthy people have an excretion 17-OKC with urine rather reliably reflects funkts, a condition of cortical substance of adrenal glands. The quantity 17-OKC is usually defined in the daily volume of urine. Normal the daily amount of urine contains from 1,31 to 7,39 mg 17-OKC, on average — 3,7 mg. The quantity 17-OKC in blood fluctuates ranging from 5 to 20 mkg in 100 ml, averaging 13 + 2,4 mkg in 100 ml. For assessment of a saturation of an organism hormones the quantity 17-OKC sometimes is expressed in terms of 1 m 2 body surfaces, 1 kg of the weight (weight) of a body or on a unit of quantity of creatinine, excretion to-rogo with urine reflects the weight (weight) of muscles. It is established that the quantity 17-OKC falling on 1 m 2 body surfaces of the person as well as secretion of a hydrocortisone, increases with age, though to a lesser extent, than daily excretion 17-OKC, and quantity 17-OKC or the speed of secretion, the bodies recalculated on 1 kg of the weight (weight), decrease a little with age.



Bibliography: Biochemistry of hormones and hormonal regulation, under the editorship of N. A. Yudayev, M., 1976; Krekhova M. A. The methods of determination of content of hormones in blood and urine used for diagnosis of a disease and Itsenko's syndrome — Cushing, in book: Sovr. vopr, endokrinol., under the editorship of N. A. Yudayev, century 5, page 102, M., 1975; Starkova H. T. The functional tests applied in diagnosis of a disease and Itsenko's syndrome — Cushing, there she, page 125; Hormones in blood, ed. by of Page H. Gray a. V. H. T. James, v. 3, p. 180, B. and. lake, 1979; Silber R. H. a. Porter C. C. The determination 17-21-dihyd-roxy-20-ketosteroids in urine and plasma, J. biol. Chem., v. 210, p. 923, 1954.


M. A. Krekhova.

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