Question

Estrogens are secreted from cells of graaffian follicle

• A. Theca interna cell
• B. Theca externa cell
• C. Luteal cell
• D. Membrne granulose cell

Hint:

To remember the "Two-Cell" model:
- Theca cells make Testosterone/Androgens (stimulated by LH).
- Granulosa cells make Estrogen (stimulated by FSH).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Ovarian follicular estrogen synthesis is explained by the "Two-Cell, Two-Gonadotropin" model, which describes the functional cooperation between theca interna and granulosa cells.

Step 3: Detailed Explanation:
The biosynthesis of estrogens within the Graafian follicle occurs as follows:
1. Theca interna cells are stimulated by Luteinizing Hormone (LH) to convert cholesterol into androgens (specifically androstenedione and testosterone).
2. These androgens diffuse across the basement membrane into the adjacent granulosa cells (referred to as membrana granulosa cells).
3. Under the influence of Follicle-Stimulating Hormone (FSH), the granulosa cells express the enzyme aromatase, which converts these diffused androgens into estrogens (principally estradiol-\(17\beta\)).
Therefore, the definitive site where estrogens are finalized, secreted, and released into the follicular fluid and circulation is the membrane granulosa cell layer.

Step 4: Final Answer
Estrogens are synthesized and secreted by the membrane granulosa cells.