- A hormone made by the outer portion (cortex) of the adrenal gland that regulates the balance of salt and water in the body. Pronounced AL·do·ste·rone. Aldosterone is secreted in response to low salt levels. Aldosterone then activates the MR (for mineralocorticoid receptor) gene. (Aldosterone is classified as a mineralocorticoid hormone.) The product of the MR gene, in turn, stimulates the kidney to reabsorb and retain salt, thereby retaining water. An MR gene mutation leads to salt retention and high blood pressure early in life which becomes much worse with pregnancy.
* * *A mineralocorticoid hormone produced by the zona glomerulosa of the adrenal cortex; its major action is to facilitate potassium exchange for sodium in the distal renal tubule, causing sodium reabsorption and potassium and hydrogen loss; the principal mineralocorticoid. It exists in equilibrium with the aldehyde form. SYN: aldocortin.
* * *al·do·ste·rone al-'däs-tə-.rōn; .al-dō-'sti(ə)r-.ōn, -stə-'rōn n a steroid hormone C21H28O5 of the adrenal cortex that functions in the regulation of the salt and water balance of the body
* * *n.a steroid hormone (see corticosteroid) that is synthesized and released by the adrenal cortex and acts on the kidney to regulate salt (potassium and sodium) and water balance. It may be given by injection as replacement therapy when the adrenal cortex secretes insufficient amounts of the hormone and also to treat shock.
* * *al·dos·ter·one (al-dosґtər-ōn) the major mineralocorticoid secreted by the adrenal cortex; it promotes retention of sodium and bicarbonate, excretion of potassium and hydrogen ions, and secondary retention of water. Large excesses can invoke plasma volume expansion, edema, and hypertension. The secretion of aldosterone is stimulated by low plasma potassium concentration and angiotensin II.
Medical dictionary. 2011.