Which hormone stimulates the adrenal cortex to produce cortisol?

• A. ACTH
• B. ADH
• C. TSH
• D. ANP

Answer: (A)

Cortisol production by the adrenal cortex is driven by adrenocorticotropic hormone (ACTH) from the anterior pituitary, which in turn is stimulated by corticotropin-releasing hormone from the hypothalamus. When ACTH binds to receptors on adrenal cortex cells, it promotes the synthesis and release of cortisol. This is all part of the hypothalamic–pituitary–adrenal axis, with cortisol exerting widespread metabolic and anti-inflammatory effects and feeding back to suppress ACTH and CRH when levels rise.

The other hormones have different targets and roles: antidiuretic hormone acts on the kidneys to conserve water; thyroid-stimulating hormone prompts the thyroid to produce T3 and T4; and atrial natriuretic peptide helps regulate blood volume and pressure via the heart and kidneys. None of these stimulate the adrenal cortex to produce cortisol.