In mammals, spermatogenesis is stimulated by

Options

A. MSH
B. TSH
C. ADH
D. FSH.

Answer

**Step-by-Step Solution:**

1. **Understanding Spermatogenesis**:
- Spermatogenesis is the biological process of sperm formation in male mammals. It occurs in the seminiferous tubules of the testes.

2. **Identifying Hormones Involved**:
- Several hormones play a role in reproductive processes, including MSH (Melanocyte-Stimulating Hormone), TSH (Thyroid-Stimulating Hormone), ADH (Antidiuretic Hormone), and FSH (Follicle-Stimulating Hormone).

3. **Analyzing Each Option**:
- **Option A: MSH** - Primarily involved in pigmentation and does not stimulate spermatogenesis.
- **Option B: TSH** - Regulates thyroid function and metabolism, not directly related to sperm production.
- **Option C: ADH** - Regulates water balance in the body and does not influence spermatogenesis.
- **Option D: FSH** - Follicle-Stimulating Hormone is crucial for the regulation of spermatogenesis.

4. **Conclusion**:
- FSH stimulates spermatogenesis by promoting the development of sperm cells and also influences the production of androgens, which are necessary for the maturation of sperm.

5. **Final Answer**:
- Therefore, the correct answer is **Option D: FSH**.

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