aldosterone (ăl'dōstĭrōn`), steroid secreted by the cortex of the adrenal gland. It is the most potent hormone hormone, 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.
..... Click the link for more information. 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 [al′däs·tə‚rōn]
Aldosterone
..... Click the link for more information. 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 [al′däs·tə‚rōn]
(biochemistry)
C21H28O5A steroid hormone extracted from the adrenal cortex that functions chiefly in regulating sodium and potassium metabolism.
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).
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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
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