Question

Hormone, interact with membrane, the secondary messenger. Which of the following is a secondary messenger?

• A. AMP
• B. T3
• C. Renin
• D. ANF

Hint:

Remember, secondary messengers like AMP amplify the signal of hormones and activate cellular responses, often by interacting with protein kinases or other signaling molecules.

Answer 1

The Correct Option is A

A secondary messenger is a molecule that acts as an intermediary in the signal transduction process. When a hormone (such as a peptide or catecholamine) binds to a receptor on the cell membrane, it activates an intracellular signaling pathway. These pathways often involve secondary messengers, which amplify the signal inside the cell.

Among the options:

AMP (Adenosine monophosphate) acts as a secondary messenger in many hormone signaling pathways, such as the one activated by glucagon and adrenaline through G-protein-coupled receptors. It is involved in the cyclic AMP pathway.
T3 (Triiodothyronine) is a thyroid hormone that interacts directly with nuclear receptors and does not function as a secondary messenger.
Renin is an enzyme involved in the renin-angiotensin system, but it is not a secondary messenger itself; it catalyzes the conversion of angiotensinogen to angiotensin I.
ANF (Atrial natriuretic factor) is a hormone that affects blood pressure and fluid balance, but it is not a secondary messenger.

Thus, AMP is the correct answer, as it is the key secondary messenger in several signaling cascades, including the activation of protein kinases in response to hormone binding to membrane receptors.