Which of the following hormones is active during proliferative phase of menstrual cycle?

Options

A. Estrogen
B. Progesterone
C. Testosterone
D. All of these

Answer

To determine which hormone is active during the proliferative phase of the menstrual cycle, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Menstrual Cycle Phases**: The menstrual cycle consists of several phases: menstrual phase, follicular phase (also known as the proliferative phase), ovulatory phase, and luteal phase. Each phase is characterized by specific hormonal changes.

2. **Identify the Proliferative Phase**: The proliferative phase corresponds to the follicular phase of the menstrual cycle. This phase occurs after menstruation and before ovulation. It typically lasts from day 6 to day 14 of the cycle.

3. **Hormonal Activity During the Proliferative Phase**: During the proliferative phase, the primary hormone involved is estrogen. Estrogen is produced by the developing follicles in the ovaries and is responsible for the thickening of the uterine lining in preparation for a potential pregnancy.

4. **Evaluate Other Hormones**:
- **Progesterone**: This hormone is primarily active during the luteal phase, after ovulation, when the corpus luteum forms.
- **Testosterone**: This is a male hormone and is not significantly involved in the menstrual cycle.
- **All of These**: This option is incorrect as only estrogen is primarily active during the proliferative phase.

5. **Conclusion**: Based on the above analysis, the hormone that is active during the proliferative phase of the menstrual cycle is **estrogen**.

### Final Answer:
The hormone that is active during the proliferative phase of the menstrual cycle is **estrogen**.

---