Aldosterone

Aldosterone is a steroid hormone (mineralocorticoid family) produced by the outer section (zona glomerulosa) of the adrenal cortex in the adrenal gland. It acts mainly on the distal tubules and collecting ducts of the nephron, the functional unit of the kidney, to cause the conservation of sodium, secretion of potassium, increased water retention, and increased blood pressure. The overall effect of aldosterone is to increase reabsorption of ions and water in the kidney -- increasing blood volume and, therefore, increasing blood pressure.