Question

Antidiuretic hormone affects the kidney by

• A. Constricting arterioles and thus raising blood pressure
• B. Increasing the reabsorption of $N{a}^{+}$ in the-distal convoluted tubules
• C. Countering the renin-angiotensin-aldosterone mechanism
• D. Increasing the water permeability of the distal convoluted tubule and collecting duct, thus increasing the osmolarity of the urine

Answer 1

The correct option is D Increasing the water permeability of the distal convoluted tubule and collecting duct, thus increasing the osmolarity of the urine

Vasopressin or antidiuretic hormone (ADH) acts mainly at the kidney and stimulates resorption of water and electrolytes by the distal tubules and thereby reduce the loss of water through urine (diuresis).

So the correct answer is increasing the water permeability of the distal convoluted tubule and collecting duct, thus increasing the osmolarity of the urine.