Which of these hormones uses cAMP as a second messenger ?

Options

A. Estrogen
B. Cortisol
C. Epinephrine
D. Testosterone

Answer

To determine which hormones use cAMP (cyclic Adenosine Monophosphate) as a second messenger, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Role of cAMP**:
- cAMP acts as a second messenger in many hormonal signaling pathways. It is crucial for transmitting signals from hormones that cannot enter the cell directly, such as peptide hormones.

2. **Identify Hormonal Types**:
- Hormones can be broadly categorized into two types:
- **Peptide (Protein) Hormones**: These are made of amino acids and cannot cross the cell membrane. They rely on second messengers like cAMP.
- **Steroid Hormones**: These are derived from cholesterol, can pass through the cell membrane, and typically do not use cAMP as a second messenger.

3. **List Common Hormones**:
- Some common hormones include:
- **Peptide Hormones**: Insulin, Glucagon, Adrenocorticotropic hormone (ACTH), and others.
- **Steroid Hormones**: Estrogen, Cortisol, Testosterone, etc.

4. **Determine Which Hormones Use cAMP**:
- Among the hormones listed, those that are peptide hormones (like Glucagon and ACTH) utilize cAMP as a second messenger to relay signals inside the cell.

5. **Conclusion**:
- Therefore, the hormones that utilize cAMP as a second messenger are primarily peptide hormones.

### Final Answer:
The hormones that use cAMP as a second messenger are peptide hormones such as Glucagon and Adrenocorticotropic hormone (ACTH).