Mineralocorticoids play an important role in water and salt balance control. They stimulate retention of sodium ions against the loss of potassium ions in urine. Mineralocorticoids bind to a mineralocorticoid-receptor in the nucleus. This complex can interact with a specific binding site on the DNA, resulting in transcription of genes. Fludrocortisone
is the only mineralocorticoid with clinical application. In Addison's the dose of fludrocortisone is between 0.05-0.2 mg daily in combination with 20 mg hydrocortisone.
I. Fludrocortisone exerts its action in the proximal tubule in the kidney. II. Mineralocorticoid deficiency can cause hypernatremia.
Extra info: Fludrocortisone acts on the distal tubule in the kidney. Aldosterone deficiency results in a decreased resorption of sodium ions and thus hyponatremia.