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Aldosterone is the primary of several endogenous members of the class of mineralocorticoids in humans. [citation needed] Deoxycorticosterone is another important member of this class. Aldosterone tends to promote Na + and water retention, and lower plasma K + concentration by the following mechanisms:
It selectively stimulates secretion of aldosterone. The secretion of aldosterone has a diurnal rhythm. Control of aldosterone release from the adrenal cortex: [citation needed] The role of the renin–angiotensin system: Angiotensin is involved in regulating aldosterone and is the core regulator. Angiotensin II acts synergistically with potassium.
In the adrenal cortex, angiotensin II acts to cause the release of aldosterone. Aldosterone acts on the tubules (e.g., the distal convoluted tubules and the cortical collecting ducts) in the kidneys, causing them to reabsorb more sodium and water from the urine. This increases blood volume and, therefore, increases blood pressure.
The mineralocorticoid receptor (or MR, MLR, MCR), also known as the aldosterone receptor or nuclear receptor subfamily 3, group C, member 2, (NR3C2) is a protein that in humans is encoded by the NR3C2 gene that is located on chromosome 4q31.1-31.2. [5] MR is a receptor with equal affinity for mineralocorticoids and glucocorticoids.
The exact mechanism(s) underpinning aldosterone escape are an active subject of research, though several mechanisms have been proposed. [ 3 ] Proposed mechanisms for this phenomenon do not include a reduced sensitivity of mineralocorticoid receptors to aldosterone, because low serum potassium is often seen in these patients, which is the direct ...
Aldosterone synthase is a protein which is only expressed in the zona glomerulosa [5] of the adrenal cortex and is primarily regulated by the renin–angiotensin system. [6] It is the sole enzyme capable of synthesizing aldosterone in humans and plays an important role in electrolyte balance and blood pressure. [7]
Sensors of blood pressure in the juxtaglomerular apparatus of the kidneys release the enzyme renin into the blood, which starts a cascade of reactions that lead to formation of angiotensin II. Angiotensin receptors in cells of the zona glomerulosa recognize the substance, and upon binding they stimulate the release of aldosterone. [31]
The name mineralocorticoid derives from early observations that these hormones were involved in the retention of sodium, a mineral.The primary endogenous mineralocorticoid is aldosterone, although a number of other endogenous hormones (including progesterone [1] and deoxycorticosterone) have mineralocorticoid function.