Ligand aldosterone

Although MR also binds glucocorticoids, its main ligand in classical mineralocorticoid target tissues such as kidney and colon is aldosterone ( d 1.3 nM). This can be granted to the ability of 11 (3-hydioxysteroid dehydrogenase type II (11 (3-HSD II) to convert active cortisol into its inactive metabolite cortisone in these tissues. Since aldosterone is no substrate for this enzyme it can readily bind to MR, leading to exclusive occupation of the receptor by aldosterone. In contrast, no such mechanism exists in brain and presumably... 

Mineralocorticoid receptor (MR) Ligand-induced homodimer Aldosterone Palindromic inverted repeat... 

The presence of excess TBW and hypernatremia indicates a net gain of water and Na, with Na gain in excess of water (see Figure 46-3). This condition is commonly observed in hospital patients receiving hypertonic saline or sodium bicarbonate. Other causes of hypervolemic hypernatremia include hyperaldosteronism and Cushing s syndrome (see Chapters 24 and 51). Excess aldosterone and cortisol (which also act as ligands for the distal tubule aldosterone receptor) results in excess Na and water retention. Corticosteroid therapy can have similar effects as weh. 

Measurement of Aldosterone in Blood and Urine Simple and refiable immunoassay methods for measuring aldosterone in blood and urine are readily available. These methods differ primarily in the specificity of the antialdosterone antibodies. Most direct radioimmunoassay methods for plasma aldosterone use antisera generated against an aldosterone-3-monooxime-bovine serum albumin (BSA) conjugate, and use an T-labeled ligand and ANS at pH 3.6 to displace aldosterone from plasma-binding proteins. ... 

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