Aldosterone	

Aldosterone is the principal mineralocorticoid that is secreted by the outermost zone of the adrenal cortex, the zona glomerulosa. Its primary effect is to increase the resorption of sodium by the distal convoluted tubule of the kidney, in exchange for potassium and hydrogen ions. Therefore, if aldosterone levels are persistently elevated, hypokalaemia and alkalosis will ensue.

See also: 
• Biosynthesis of Steroid Hormones