ALDOSTERONE - Aldosterone is a hormone which is produced by the adrenal glands. Aldosterone increases the reabsorption of sodium (and the excretion of potassium) by the distal tubules in the kidney. The reabsorption of sodium results in an increased reabsorption of water which can result in hypertension. Low blood aldosterone levels are seen in Addison's disease and toxemia of pregnancy. Higher levels can be seen in Cushing's syndrome, primary hyperaldosteronism, malignant hypertension, severe swelling in congestive heart failure, and nephrotic syndrome.