Q. Which one of the following is not a second messenger in hormone action ?
A) cGMP
B) Calcium
C) Sodium
D) cAMP
Explanation
[Solution from source] cAMP, cGMP and Ca²⁺ act as second messengers that relay hormone signals inside the cell. Sodium ions are not used as second messengers. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.