Aldosterone


Actions

  • stimulates sodium re-absorption from lumen of distal nephron in exchange for potassium or hydrogen
    • induces formation of proteins involved in sodium transport

Release

  •  stimulated by angiotensin II
    • renin release by decrease in perfusion pressure in afferent arterioles of kidney
    • cleaves angiotensinogen to angiotensin I
    • angiotensin I converted to angiotensin II by converting enzyme in endothelial cells
  • plasma potassium concentration and ACTH also stimulate aldosterone release

Drugs

  • spironolactone
    • blocks actions of aldosterone

Problems

  • Hyperaldosteronism (Conn's syndrome if caused by adrenal adenoma)
    • in excess blood volume increased so hypertension,
    • continued high potassium excretion leads to Hypokalaemia

Metabolism

  • in liver then conjugated with a glucuronide for excretion in urine
  • increased sodium transport leads to increased potassium excretion
  • in excess blood volume increased so hypertension, continued high potassium excretion leads to hyperkalemia

14.4.2.2 Aldosterone

mineralocorticoid action to regulate body sodium and water
control of mineralocorticoid secretion via renin-angiotensin, ANP, ions
dysfunction: aldosterone excess (Conn’s)
 

 


Home ] Up ]