What is the hormone secreted by the anterior lobe of the pituitary gland that stimulates the adrenal cortex?

The hormone that stimulates the adrenal cortex is corticotropin, also known as adrenocorticotropic hormone (ACTH). This hormone is secreted by the anterior lobe of the pituitary gland and plays a crucial role in the body’s stress response. When released, corticotropin acts on the adrenal cortex, prompting it to produce and release glucocorticoids, including cortisol. These hormones are vital for various bodily functions, such as metabolism regulation, inflammation control, and the body's response to stress.

Corticotropin is particularly important in the hypothalamic-pituitary-adrenal (HPA) axis, where it acts in response to signaling from the hypothalamus. This ensures that the body can mount an appropriate response to stressors by increasing cortisol levels and other related hormones.

The other choices represent different hormones with distinct functions. Thyroxine, for instance, is produced by the thyroid gland and primarily regulates metabolism. Prolactin is involved in lactation and reproductive functions, while growth hormone is essential for growth and cell reproduction. These hormones do not stimulate the adrenal cortex, highlighting corticotropin's specific role in the endocrine system.