Site of action of ADH is:March 2008
Ans. D: Collecting ductsBecause one of its principal physiologic effects is the retention of water by the kidney, vasopressin is often called the antidiuretic hormone (ADH).It increases the permeability of the collecting ducts of the kidney, so that water enters the hypeonic interstitium of the renal pyramids.The urine becomes concentrated, and its volume decreases. The overall effect is therefore retention of water in excess of solute; consequently, the effective osmotic pressure of the body fluids is decreased. In the absence of vasopressin, the urine is hypotonic to plasma, urine volume is increased, and there is a net water loss. Consequently, the osmolality of the body fluid rises.
PCT
Vasa recta
Loop of henle
Collecting ducts