Physiology of the adrenal cortex
Endocrinology / / May 24, 2016
hormones of the adrenal cortex
first bioactive extracts of the adrenal cortex that can prevent the death of adrenalectomized animals were received in 1930 (Hartman u Brow-nell; Swingle and Pfiffner.).In 1934, Kendall et al.and in 1935 Wintersteiner et al.extracts isolated from adrenal crystalline substances possessing biological activity.During the period from 1935 to 1938 in three groups of chemists led by Kendall, Wintersteiner, Reichenstein of adrenal extracts it was allocated about thirty steroids, six of which have biological activity.
In 1937-1944 gg.It was synthesized by a number of steroids among those detected in extracts of the adrenal gland, including deoxycorticosterone, corticosterone and cortisone.In 1950, the synthesis of hydrocortisone.In 1952, of the adrenal steroid selected extracts having a high mineralocorticoid activity - aldosterone.
chemical structure and classification of biologically active steroids produced by the adrenal cortex.It is now known that is produced in the adren
Depending on the number of carbon atoms in the side chains, joining to main cyclopentano-pergidrofenantrenovomu nucleus adrenocortical hormones belong to three groups of compounds:
1) pregnane derivatives or allopregnana containing 21 carbon atoms,
2) androstane derivatives containing 19carbon atoms,
3) estrane derivatives containing 18 carbon atoms.
group of compounds related to derivatives of pregnane - corticosteroids, corticoids or - has a biological activity which is specific for the adrenal cortex hormones.
This group includes eight steroids - cortisol (hydrocortisone, 17-a-hydroxy corticosterone), cortisone (17-a-hydroxy-11-dehydrocorticosterone), corticosterone, 17-A-oxy-11-deoxycorticosterone, 11-degidrokortiko of testosterone19-oksikortikosteron, 11-deoxycorticosterone and aldosterone.Under physiological conditions, only three hormones enter the bloodstream in the amounts determined - cortisol, corticosterone and aldosterone.The other compounds undergo further transformations in the adrenal gland.
By its action on metabolic processes corticosteroids received in the blood fall on glucocorticoid and mineralocorticoid.
To include glucocorticoid cortisol and corticosterone.Cortisone glikokortikoidnoy having pronounced activity without adrenal blood flows into the vein, but apparently can be formed of a cortisol metabolism in adrenal gland is the last.This is evidenced by the fact that, although detected cortisone can not be blood in the urine revealed his tetragidrosoedineniya.
To apply mineralocorticoid aldosterone.Deoxycorticosterone, which is an important intermediate in the synthesis of corticosteroids in the adrenal cortex, and has a pronounced effect on the exchange of electrolytes, according to modern concepts, enters the blood from the adrenal glands only under certain pathological conditions.
separation between mineralocorticoid and glikortikoidami is to some extent arbitrary, since hormones between these groups there is a zone of "functional overlap."Glucocorticoid - cortisol, cortisone and corticosterone even greater extent - have an exchange of electrolytes - potassium ions and sodium - the same effect as aldosterone, but it mineralocorticoid action expressed their relatively weak.On the other hand, of aldosterone affects certain metabolic processes, like cortisol, it is significantly inferior in activity.
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Another group of steroids produced by the adrenal cortex - her beam area - and having biological activity, make sex hormones and 17-keto steroids.True
hormones - a highly active androgen hormone testosterone and estrogens - estrone and estradiol - are produced in the adrenal gland in small amounts.Progesterone, which is an important intermediate in the biosynthesis of corticosteroids, are also released into the blood in small amounts.Of the large number (about 20) of the currently known compounds, grouped under the name of 17-ketosteroids and characterized by the presence of the keto group at the 17 th carbon atom, adrenal vein blood detected three neutral-ketosteroid 17 - DHEA (dehydroisoandrosterone), androstenedione, 11-gidroksiandrostendion.These compounds have the properties of the male sex hormone, but they are considerably less active than testosterone.The most active of the 17-keto steroids produced by the adrenal cortex - androstendion- five times weaker than testosterone and androgenic properties of two other 17-keto steroids less.In addition to the 17-keto steroids produced by the adrenal cortex, during the metabolism of corticosteroids is formed in the body and excreted in urine are a number of neutral-17 ketosteroids, androsterone of which has weak androgenic activity.
02 May, 2016
02 May, 2016
02 May, 2016