Question

Which one of the following hormone causes reabsorption of $N{a}^{+}$ ions from the distal parts of the renal tubule?

• A. Renin
• B. ADH
• C. Aldosterone
• D. ANF

Answer 1

Answer: (C)

Aldosterone

Whenever the kidneys sense a decrease in blood pressure, they release a hormone called Renin. Renin acts on the activation of angiotensin to angiotensin-I in the liver. Angiotensin-I is a vasoconstrictor that allows an increase in blood pressure. This angiotensin-II is soon converted to angiotensin-II which is a powerful vasoconstrictor and it results in secretion of aldosterone from the adrenal gland. The aldosterone is directly involved in increasing the resorption of Na${}^{+}$ ion from the distal convoluted tubule, due to which the water retention is facilitated and the blood pressure can be increased.

A. Renin is indirectly involved in increasing blood pressure.

B. ADH acts on the water porins directly rather than on ionic reabsorption.

C. Aldosterone allows retention of water through the reabsorption of Na${}^{+}$ ions from the distal part of the renal tubule.

D. Atrial Natriuretic Peptide is involved in decreasing the blood pressure.

Hence, the correct answer is 'Aldosterone'