What hormone promotes active tubular secretion of potassium ions and reabsorption of sodium ions in the distal convoluted tubule (DCT) and collecting ducts?

aldosterone

Explanation:

Aldosterone is the hormone which is produced in outer section of adrenal glands which are situated above kidneys. The hormone plays central role in regulation of the blood pressure by acting on the organs like kidney and colon to increase amount of the sodium reabsorbed into bloodstream and to increase amount of the potassium excreted in urine. Aldosterone also causes the water to be reabsorbed in the blood stream along with the sodium and thus increasing blood volume.