Which ovarian cells are responsible for converting androstenedione to estradiol during the menstrual cycle?

Granulosa cells play a crucial role in the conversion of androstenedione to estradiol during the menstrual cycle. This conversion process occurs primarily in the ovarian follicles during the follicular phase and is vital for the development and maturation of oocytes as well as the regulation of the menstrual cycle.

In the ovarian follicle, theca interna cells produce androstenedione and testosterone in response to luteinizing hormone (LH). However, these androgens cannot be converted directly to estradiol. Granulosa cells have the enzyme aromatase, which allows them to convert the androgens produced by the Theca interna into estradiol when stimulated by follicle-stimulating hormone (FSH). This conversion process is essential for the synthesis of estrogen, which supports the proliferation of the endometrial lining in preparation for potential implantation.

The activity of granulosa cells is regulated during different phases of the menstrual cycle and is crucial for proper ovarian function and reproductive health. The importance of the granulosa cells in producing estradiol underscores their role in the overall hormonal balance necessary for fertility.