arrow
arrow
arrow
​The reabsorption of water and NaCl in kidneys is inhibited by the increased secretion of the following substances EXCEPT one:​
Question

The reabsorption of water and NaCl in kidneys is inhibited by the increased secretion of the following substances EXCEPT one:

A.

Urodilatin

B.

Uroguanylin

C.

Dopamine

D.

Norepinephrine

Correct option is D

Explanation-

The kidney regulates reabsorption of water and sodium chloride (NaCl) in the nephron to control blood volume, pressure, and osmolality. Some substances inhibit reabsorption (i.e., promote excretion of Na⁺ and H₂O), and some stimulate reabsorption.
Option D - Norepinephrine
It is a sympathetic neurotransmitter which timulates Na⁺ and water reabsorption by activating α-adrenergic receptors, increasing renin secretion → RAAS activation → Aldosterone release and vasoconstriction of renal vessels.
So, norepinephrine increases water and salt reabsorption, unlike the others.

Incorrect options-

Option A - Urodilatin
A natriuretic peptide secreted by kidney cells.
Function: Inhibits Na⁺ and water reabsorption in the collecting duct.
Thus, it reduces reabsorption.
Option B - Uroguanylin
it is secreted by the gut, acts on kidneys. It binds to guanylate cyclase receptors in the nephron. It promotes natriuresis (Na⁺ excretion) and diuresis (water loss).
Thus , inhibits reabsorption.
Option C -  Dopamine
In the renal tubules, dopamine acts as a natriuretic hormone. It reduces Na⁺ reabsorption by inhibiting Na⁺/K⁺ ATPase.
Thus , inhibits reabsorption.

So, option D - Norepinephrine is the correct answer.

Similar Questions

test-prime-package

Access ‘CSIR NET Life Sciences’ Mock Tests with

  • 60000+ Mocks and Previous Year Papers
  • Unlimited Re-Attempts
  • Personalised Report Card
  • 500% Refund on Final Selection
  • Largest Community
students-icon
446k+ students have already unlocked exclusive benefits with Test Prime!
test-prime-package

Access ‘CSIR NET Life Sciences’ Mock Tests with

  • 60000+ Mocks and Previous Year Papers
  • Unlimited Re-Attempts
  • Personalised Report Card
  • 500% Refund on Final Selection
  • Largest Community
students-icon
446k+ students have already unlocked exclusive benefits with Test Prime!

Similar Questions

Our Plans
Monthsup-arrow