Name the hormone that influences secretion of estrogen.

Explanation

**Step-by-Step Solution:**

1. **Understanding Estrogen**: Estrogen is a key female reproductive hormone primarily produced by the ovaries. It plays a vital role in the regulation of the female reproductive system.

2. **Production Sites**: While the ovaries are the main site of estrogen production, during pregnancy, the placenta also contributes to the secretion of estrogen.

3. **Role of Follicle Stimulating Hormone (FSH)**: The secretion of estrogen is influenced by the Follicle Stimulating Hormone (FSH). FSH is crucial for the maturation of ovarian follicles, which are responsible for producing estrogen.

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