Got_Aldosterone - GotAldosterone? AldosteroneSynthesis...

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Got Aldosterone?
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Aldosterone Synthesis Aldosterone is produced in the zona glomerulosa of the adrenal gland The enzyme aldosterone synthase encoded by the gene CYP11B2 gene converts deoxycorticosterone to aldosterone via a series of steps In glucocorticoid remediable aldosteronism (GRA), a chimeric gene containing the promotor sequence of CYP11B1 and functional elements of CYP11B2 is created, resulting in aldosterone production under the control of ACTH
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Mineralocorticoid Receptor (MR) Aldosterone acts by diffusing into cells and attaching to a specific receptor, mineralocorticoid receptor (MR) in the cytosol which then leads to the synthesis of new proteins called aldosterone-induced proteins (AIPs). Cortisol binds to the MR receptor at equal affinity and is found in much higher concentrations then that of aldosterone. However target cells contain 11ß- hydroxysteroid dehydrogenase that converts cortisol to cortisone which is inactive. If 11ß-hydroxysteroid dehydrogenase is inactivated, such as in the syndrome of apparent mineralocorticoid excess , or inhibited such as occurs in chronic ingestion of licorice patients can present with findings similar to hyperaldosteronism. MR are found in high concentrations in the renal distal nephron as well as the colon and sweat and salvary glands, but also has been found in the heart, brain, vascular smooth muscle, liver, and blood leukocytes
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Action on Renal Tubular Cells Aldosterone promotes the reabsorption of NaCl and the secretion of K+ in the principal cells in the cortical collecting tubules The intercalated cells in the cortex contain MR and aldosterone enhances H+ secretion via H+-ATPase pumps in the apical membrane. Na+ reabsoprtion via the principal cells causes a lumen-negative
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Got_Aldosterone - GotAldosterone? AldosteroneSynthesis...

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