Assertion (A). Hormones interacting with cell surface receptors do not enter the target but they generate second messenger
Reason (R ). Glucocorticoids bind to intracellular receptors and regulate gene expression

Options

A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false and R is true.

Answer

To solve the question regarding the assertion and reason provided, we will analyze both statements step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that hormones interacting with cell surface receptors do not enter the target cell but generate second messengers.
- This is true for peptide hormones (like insulin), which bind to receptors on the cell surface and initiate a signaling cascade that produces second messengers such as cyclic AMP (cAMP).

2. **Understanding the Reason (R)**:
- The reason states that glucocorticoids bind to intracellular receptors and regulate gene expression.
- This is also true. Glucocorticoids are steroid hormones that can pass through the cell membrane due to their lipid-soluble nature. Once inside the cell, they bind to specific intracellular receptors and influence gene expression by acting on the DNA.

3. **Evaluating the Relationship Between A and R**:
- While both the assertion and reason are correct, they address different mechanisms of hormone action. The assertion refers to peptide hormones and their action via cell surface receptors, while the reason discusses steroid hormones (like glucocorticoids) and their action through intracellular receptors.
- Therefore, the reason does not explain the assertion, as they pertain to different types of hormones.

4. **Conclusion**:
- Based on the analysis, the correct option is that both A and R are true, but R is not the correct explanation of A.

### Final Answer:
Both A and R are true, but R is not the correct explanation of A.

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