Question:easy
Nitric oxide acts by increasing which of the following?
Nitric oxide acts by increasing which of the following?
Show Hint
NO activates guanylate cyclase, raising the cyclic nucleotide derived from GTP.
Updated On: Jun 23, 2026
- BRCA 1
- BRCA 2
- Interleukin
- cGMP
Show Solution
The Correct Option is D
Solution and Explanation
Step 1: Identify the pathway. Nitric oxide is the classic endothelium-derived relaxing factor, so we expect a second-messenger answer linked to vasodilation.
Step 2: NO binds the haem group of soluble guanylate cyclase. This enzyme then makes $cGMP$ from $GTP$, so the immediate measurable effect of NO is a jump in cellular $cGMP$.
Step 3: Elevated $cGMP$ drives protein kinase G, reduces cytosolic calcium and relaxes vascular smooth muscle. This explains why nitrates and PDE-5 inhibitors (which preserve cGMP) cause vasodilation.
Step 4: Eliminate the rest - BRCA1 and BRCA2 are DNA-repair genes tied to breast and ovarian cancer, and interleukins are immune messengers; none are downstream of NO. The signalling molecule increased is cyclic GMP.\[\boxed{cGMP}\]
Step 2: NO binds the haem group of soluble guanylate cyclase. This enzyme then makes $cGMP$ from $GTP$, so the immediate measurable effect of NO is a jump in cellular $cGMP$.
Step 3: Elevated $cGMP$ drives protein kinase G, reduces cytosolic calcium and relaxes vascular smooth muscle. This explains why nitrates and PDE-5 inhibitors (which preserve cGMP) cause vasodilation.
Step 4: Eliminate the rest - BRCA1 and BRCA2 are DNA-repair genes tied to breast and ovarian cancer, and interleukins are immune messengers; none are downstream of NO. The signalling molecule increased is cyclic GMP.\[\boxed{cGMP}\]
Was this answer helpful?
0
