aldosterone

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aldosterone

(ăl'dōstĭrōn`), steroid secreted by the cortex of the adrenal gland. It is the most potent hormonehormone,
secretory substance carried from one gland or organ of the body via the bloodstream to more or less specific tissues, where it exerts some influence upon the metabolism of the target tissue.
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 regulating the body's electrolyte balance. Aldosterone acts directly on the kidney to decrease the rate of sodium-ion excretion (with accompanying retention of water), and to increase the rate of potassium-ion excretion. The secretion of aldosterone appears to be regulated by two mechanisms. First, the concentration of sodium ions may be a factor since increased rates of aldosterone secretion are found when dietary sodium is severely limited. Second, reduced blood flow to the kidney stimulates certain kidney cells to secrete the proteolytic enzyme renin, which converts the inactive angiotensinogen globulin in the blood into angiotensin I. Another enzyme then converts angiotensin I into angiotensin II, its active form. This peptide, in turn, stimulates the secretion of aldosterone by the adrenal cortex. Pathologically elevated aldosterone secretion with concomitant excessive retention of salt and water often results in edema.

Aldosterone

The steroid hormone found in the biologically active amorphous fraction that remains after separation of the various crystalline steroid substances, such as cortisol and corticosterone, from adrenal extracts. In solution, aldosterone exists as an equilibrium mixture of aldo and lactol forms (see illustration).

Structures for two forms of aldosterone in an equilibrium mixture, ( a ) aldo and ( b ) lactolenlarge picture
Structures for two forms of aldosterone in an equilibrium mixture, (a) aldo and (b) lactol

The chief function of aldosterone is the regulation of electrolyte metabolism, that is, promotion of sodium retention and enhancement of potassium excretion. Aldosterone is the most potent of the hormones which are concerned in this type of metabolism. See Adrenal gland, Hormone, Steroid

Aldosterone

 

(also electrocortin, or aldocortin), an adrenocortical hormone of the group of corticosteroids. It regulates mineral metabolism in the organism and is the basic mineralocorticoid. The molecular mass is 360.43.

Aldosterone was isolated in a crystalline form in 1953 and synthesized in 1959 by Wettstein. It helps to retain sodium ions (Na+) in the organism and to eliminate potassium ions (K+) in the urine, saliva, and perspiration. A deficiency of Na+ and an elevated K+ content in food lead to an increase in the formation of aldosterone. An insufficiency of aldosterone—for example, with adrenalectomy or with Addison’s disease—leading to an acute loss of Na, imperils the life of the organism. The increased formation of aldosterone—for example, with adrenal tumors and certain heart and kidney diseases—causes the retention of water in the organism (edema), an increase in blood pressure, and so forth. The level of aldosterone secretion is related to the relative Na+ and K+ content in the blood plasma and is regulated by the mesencephalon, which secretes the neurohormone adrenoglomerulotropine with the participation of angiotensin and renin, which is formed in the kidneys and the vegetative nervous system.

REFERENCE

Berzin, T. Biokhimiia gormonov. Moscow, 1964. Page 259. (Translated from the German.)

G. L. SHREIBERG

aldosterone

[al′däs·tə‚rōn]
(biochemistry)
C21H28O5 A steroid hormone extracted from the adrenal cortex that functions chiefly in regulating sodium and potassium metabolism.
References in periodicals archive ?
Aldosterone antagonists confer additional mortality benefit but require close monitoring for the development of severe hyperkalemia and renal dysfunction.
This reluctance may in part be due to uncertainty about the safety and effectiveness of aldosterone antagonists under real-world conditions.
Estimated percentage of patients who are prescribed Diuretics, Beta Blockers (adrenergic receptor antagonists), Alpha Blockers (adrenergic receptor antagonists), Adrenergic Receptor Agonists, Calcium Channel Blockers, ACE Inhibitors, Angiotensin II Receptor Antagonists, Statins, Aldosterone Antagonists, Centrally Acting Antihypertensives, Vasodilators or other (specified).
In the light of the recent EMPHASIS-HF data, the third outcome trial for aldosterone antagonists that demonstrated a significant mortality reduction in heart failure patients, RLY5016 holds great promise in managing hyperkalemia and enabling the use of these life-saving drugs.
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Aldosterone antagonists may prove to be beneficial in all patients who take angiotensin-converting enzyme inhibitors or angiotensin receptor blockers.
Their results also suggest further evaluation of aldosterone antagonists is warranted as another possible risk factor.
Key unmet need: The prevention of worsening renal function was highlighted by cardiologists as one of the most pertinent unmet needs relating to the treatment of CHF and is an issue associated with the use of aldosterone antagonists.
The renin-angiotensin-aldosterone system (RAAS) is widely accepted as the key pathway in the regulation of blood pressure and body volume and has been the target for a cocktail of antihypertensive drugs that include angiotensin receptor blockers (ARBs), angiotensin-converting-enzyme (ACE) inhibitors, aldosterone antagonists and more recently the direct renin inhibitors (DRIs).
The guidelines contain "critical" new indications for the use of aldosterone antagonists, Dr.
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