Optometry Admission Test (OAT) Practice

What does adrenocorticotropic hormone (ACTH) stimulate?

1. Thyroid hormone production

2. Milk production in the mammary glands

3. Corticosteroid production in the adrenal cortex

4. Bone and muscle growth

The correct answer is: Corticosteroid production in the adrenal cortex

Adrenocorticotropic hormone (ACTH) plays a crucial role in the endocrine system by stimulating the adrenal cortex, the outer layer of the adrenal glands, to produce corticosteroids. These hormones are vital for various bodily functions, including stress response, immune response regulation, and metabolism processes. When ACTH is released from the anterior pituitary gland in response to feedback from the hypothalamus, it targets the adrenal cortex specifically, prompting it to release glucocorticoids like cortisol, and mineralocorticoids, both of which have critical roles in maintaining homeostasis. In contrast, other options relate to different hormones or areas of hormone production not influenced by ACTH. For instance, thyroid hormone production is primarily stimulated by thyroid-stimulating hormone (TSH) instead of ACTH. Milk production in the mammary glands is controlled by prolactin, not ACTH. Bone and muscle growth is stimulated by growth hormone (GH) and other factors rather than via ACTH. Thus, the role of ACTH is specifically centered around promoting steroid hormone production in the adrenal cortex.