Ovulation in mammals occurs mainly under the influence of `:`

Options

A. TSH and ACTH
B. FSH and LH
C. TSH and STH
D. MTH and ACTH

Answer

To answer the question "Ovulation in mammals occurs mainly under the influence of:", we will analyze the options provided and identify the hormones responsible for ovulation.

### Step-by-Step Solution:

1. **Understanding Ovulation**:
- Ovulation is the process where an ovum (egg) is released from the ovary. This typically occurs around the 14th day of the menstrual cycle in mammals.

2. **Identifying Key Hormones**:
- The main hormones involved in the regulation of ovulation are gonadotropins, specifically Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH). These hormones are secreted by the pituitary gland.

3. **Role of Luteinizing Hormone (LH)**:
- LH plays a crucial role in triggering ovulation. Its levels peak around the middle of the menstrual cycle, which is when ovulation occurs. LH is responsible for the release of the mature ovum from the follicle.

4. **Role of Follicle Stimulating Hormone (FSH)**:
- FSH works alongside LH to stimulate the growth of ovarian follicles. However, it is LH that is primarily responsible for the actual process of ovulation.

5. **Eliminating Incorrect Options**:
- The other options provided (TSH and ACTH, TSH and STH, MTH and ACTH) do not play a direct role in ovulation. TSH (Thyroid Stimulating Hormone) and ACTH (Adrenocorticotropic Hormone) are involved in the regulation of the thyroid and adrenal glands, respectively, but not in the ovulation process.

6. **Conclusion**:
- Based on the above analysis, the correct answer is that ovulation in mammals occurs mainly under the influence of FSH and LH, with a primary emphasis on LH for the actual release of the ovum.

### Final Answer:
**Ovulation in mammals occurs mainly under the influence of FSH and LH.**