Question

antidiuretic hormone action
what is the primary effect of antidiuretic hormone (adh, or vasopressin)?
water retention by the kidneys
increases urine production by the kidneys
sodium retention by the kidneys
blood glucose regulation

Explanation:

Antidiuretic hormone (ADH) acts on the kidneys. Its main role is to increase the permeability of the collecting ducts in the kidneys to water. This allows more water to be reabsorbed back into the bloodstream from the filtrate in the kidneys. As a result, less water is lost in urine, which means water is retained by the kidneys.

• Option "Increases urine production by the kidneys" is incorrect because ADH reduces urine volume (by retaining water), not increasing it.
• Option "Sodium retention by the kidneys" is mainly related to hormones like aldosterone, not ADH.
• Option "Blood glucose regulation" is the function of hormones like insulin and glucagon, not ADH.

Answer:

Water retention by the kidneys