Mineralocorticoid

From Free net encyclopedia

(Difference between revisions)

Current revision

Mineralocorticoids is a class of steroids characterised by their similarity to aldosterone and their influence on salt and water metabolism.

[edit]

Physiology

The only endogenous mineralocorticoid is aldosterone, although a number of hormones (mainly progesterone) 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 principle 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.

[edit]

Pathophysiology

Hyperaldosteronism (the syndrome caused by elevated aldosterone) generally results from adrenal neoplasms. The two main resulting problems:

Hypertension and edema due to excessive Na+ and water retention.
Accelerated excretion of potassium ions. With extreme K+ loss there is muscle weakness and eventually paralysis.

Underproduction, or hypoaldosteronism, 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.

[edit]