Which hormones promote growth of ovarian follicles and production of estradiol in females?

• A. LH alone
• B. FSH alone
• C. FSH and LH
• D. Testosterone

Answer: (C)

Growth and estrogen production in the developing ovarian follicle rely on both FSH and LH working together in different cell types of the follicle. FSH acts on granulosa cells to stimulate their proliferation and, crucially, to increase aromatase activity. Aromatase converts androgens into estradiol, so this hormone directly drives the production of estradiol as the follicle matures.

LH, on the other hand, acts on the theca interna cells to produce androgens such as androstenedione. These androgens then serve as the substrate for the granulosa cells to convert into estradiol under the influence of FSH-enhanced aromatase. Without LH, the substrate for estrogen synthesis would be limited; without FSH, granulosa cells wouldn’t proliferate or efficiently produce estrogen.

So, the growth of follicles and their estradiol production depend on the cooperative action of both hormones: FSH expanding the follicle and promoting estrogen synthesis, and LH supplying the androgen substrates that become estradiol.