Name the principal mineralo-corticoid secreted by adrenal cortex. What stimulates its secretion? Mention its two functions. What is the disorder caused due to hyper-secretion of this hormone.
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 and deoxycorticosterone) have mineralocorticoid function.
Aldosterone acts on the kidneys to provide active reabsorption of sodium and an associated passive reabsorption of water, as well as the active secretion of potassium in the principal cells of the cortical collecting tubule and active secretion of protons via proton ATPases in the lumenal membrane of the intercalated cells of the collecting tubule. This in turn results in an increase of blood pressure and blood volume.
Aldosterone is produced in the zona glomerulosa of the cortex of the adrenal gland and its secretion is mediated principally by angiotensin II but also by adrenocorticotrophic hormone (ACTH) and local potassium levels.
Hyperaldosteronism (the syndrome caused by elevated aldosterone) is commonly caused by either idiopathic adrenal hyperplasia or by an adrenal adenoma. The two main resulting problems:
- Hypertension and edema due to excessive Na+ and water retention.
- Accelerated excretion of potassium ions(K+). With extreme K+ loss there is muscle weakness and eventually paralysis.
Hypoaldosteronism (the syndrome caused by underproduction of aldosterone) leads to the salt-wasting state associated with Addison's disease, although classical congenital adrenal hyperplasia and other disease states may also cause this situation. Acute underproduction (hemorrhagic adrenalitis) is often lifethreatening.
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 and deoxycorticosterone) have mineralocorticoid function.
Aldosterone acts on the kidneys to provide active reabsorption of sodium and an associated passive reabsorption of water, as well as the active secretion of potassium in the principal cells of the cortical collecting tubule and active secretion of protons via proton ATPases in the lumenal membrane of the intercalated cells of the collecting tubule. This in turn results in an increase of blood pressure and blood volume.
Aldosterone is produced in the zona glomerulosa of the cortex of the adrenal gland and its secretion is mediated principally by angiotensin II but also by adrenocorticotrophic hormone (ACTH) and local potassium levels.
Hyperaldosteronism (the syndrome caused by elevated aldosterone) is commonly caused by either idiopathic adrenal hyperplasia or by an adrenal adenoma. The two main resulting problems:
- Hypertension and edema due to excessive Na+ and water retention.
- Accelerated excretion of potassium ions(K+). With extreme K+ loss there is muscle weakness and eventually paralysis.
Hypoaldosteronism (the syndrome caused by underproduction of aldosterone) leads to the salt-wasting state associated with Addison's disease, although classical congenital adrenal hyperplasia and other disease states may also cause this situation. Acute underproduction (hemorrhagic adrenalitis) is often lifethreatening.
