Question

Which of the following is a powerful vasconstrictor that increases the glomerular blood pressure and there the GFR?

• A. Renin
• B. Angiotensin-II
• C. Aidosterone
• D. ANF

Answer 1

The correct option is B Angiotensin-II

Osmoreceptors in the body are activated by changes in blood volume, body fluid volume and ionic concentration. A fall in glomerular blood flow/glomerular blood pressure/GFR can activate the JG cells to release renin which converts angiotensinogen in blood to angiotensin I and further to angiotensin II. Angiotensin II, being a powerful vasoconstrictor, increases the glomerular blood pressure and thereby GFR. Angiotensin II also activates the adrenal cortex to release aldosterone. Aldosterone causes reabsorption of Na${}^{+}$ and water from the distal parts of the tubule. This also leads to an increase in blood pressure and GFR. This complex mechanism is generally known as the Renin-Angiotensin mechanism.

So, the correct option is 'Angiotensin-II'.