When level of androgens and estrogens fall below the set points, the __________ stops inhibiting the pituitary gland, thus permitting it to stimulate the release of sex hormones by the gonads.

When level of androgens and estrogens fall below the set points, the __________ stops inhibiting the pituitary gland, thus permitting it to stimulate the release of sex hormones by the gonads.

• A. Thyroid
• B. Adrenal gland
• C. Hypothalamus
• D. Feedback loop

Answer: (C)

The main idea is how the hypothalamic–pituitary–gonadal axis uses negative feedback to regulate sex hormone production. The hypothalamus sends GnRH to the pituitary, which then stimulates LH and FSH to drive the gonads to make androgens and estrogens. When circulating levels of these sex steroids fall below set points, the negative feedback on the hypothalamus and pituitary is reduced. That relief from inhibition allows GnRH release to rise, which in turn prompts the pituitary to increase LH and FSH secretion, boosting the gonads’ production of sex hormones. This is why the hypothalamus is the correct choice: it is the brain region that modulates pituitary activity in response to hormone levels.

The main idea is how the hypothalamic–pituitary–gonadal axis uses negative feedback to regulate sex hormone production. The hypothalamus sends GnRH to the pituitary, which then stimulates LH and FSH to drive the gonads to make androgens and estrogens. When circulating levels of these sex steroids fall below set points, the negative feedback on the hypothalamus and pituitary is reduced. That relief from inhibition allows GnRH release to rise, which in turn prompts the pituitary to increase LH and FSH secretion, boosting the gonads’ production of sex hormones. This is why the hypothalamus is the correct choice: it is the brain region that modulates pituitary activity in response to hormone levels.