Mineralocorticoids , also mineralocorticoids , belong to the corticosteroids , a class of steroid hormones from the adrenal cortex . The name refers to their role in regulating the potassium / sodium balance and therefore blood pressure . The two most important natural mineralocorticoids are aldosterone (activating) and deoxycorticosterone (inactivating). Like the glucocorticoids , the mineralocorticoids are descendants of progesterone (Δ4-pregnene-3,20-dione).
Mineralocorticoids are similar to glucocorticoids, but they mainly affect the body's water and mineral balance.
By activating the mineralocorticoid receptor, mineralocorticoids increase the reabsorption of sodium in the distal tubule of the kidney and increase the excretion of potassium . The water excretion follows the sodium, therefore the mineralocorticoids (to a lesser extent also other corticoids) increase the water content in the body.
As with all steroids , the biosynthesis of the corticoids starts with cholesterol , which is either ingested with food or (in much larger quantities) is formed from mevalonate . The intermediate product is pregnenolone , which is converted to corticosterone in two ways and this is converted to aldosterone in two steps .
Mineralocorticoid metabolism pathology
Of the enzymes involved in the biosynthesis and breakdown of mineralocorticoids, four can be affected by rare hereditary diseases that result in a deficiency in the respective enzyme:
- 3 β- hydroxysteroid dehydrogenase ( adrenogenital syndrome type 2)
- Steroid 21 hydroxylase ( adrenogenital syndrome type 3)
- Steroid 11 β -hydroxylase CYP11B1 ( adrenogenital syndrome type 4)
- Steroid 11 β -hydroxylase CYP11B2 ( hypoaldosteronism CMO I and II)
There is also a hereditary disease in which the activity of CYP11B2 is increased and leads to hyperaldosteronism .
The only synthetic mineralocorticoid is fludrocortisone , which is used clinically for primary insufficiency of the adrenal cortex in adrenogenital syndromes . It is easier and more common in practice to influence the natural aldosterone effect by antagonizing diuretics (water tablets), which are summarized as " potassium-sparing diuretics ". In contrast to thiazide diuretics , there is no insulin resistance . Other uses are for high blood pressure and after a heart attack .
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