Which hormone stimulates the release of cortisol by the adrenal cortex?

• A. TSH
• B. FSH
• C. LH
• D. ACTH

Answer: (D)

Cortisol release from the adrenal cortex is driven by ACTH from the anterior pituitary, which in turn is controlled by CRH from the hypothalamus as part of the hypothalamic-pituitary-adrenal axis. ACTH binds to receptors on adrenal cortical cells, raising cAMP and activating protein kinase A, which boosts the production of steroidogenic enzymes and promotes the conversion of cholesterol into cortisol. This results in cortisol release into the bloodstream, and cortisol then provides negative feedback to dampen both CRH and ACTH production. The other hormones listed regulate other glands—TSH stimulates the thyroid, while FSH and LH act on the gonads—so they do not stimulate cortisol release.