Which of the following hormones is primarily involved in the stress response?

The hormone primarily involved in the stress response is adrenocorticotropic hormone (ACTH). When an individual perceives a stressor, the hypothalamus signals the pituitary gland to release ACTH into the bloodstream. This hormone then travels to the adrenal glands, stimulating them to produce cortisol, a key stress hormone that helps the body manage stress by increasing glucose availability, enhancing brain function, and curbing non-essential functions in a fight-or-flight situation.

While norepinephrine does play a role in the stress response, as it is released from the sympathetic nervous system and helps prepare the body for immediate action, its role is more about the acute response to stress rather than the longer-term hormonal regulation that ACTH influences through cortisol production. Dopamine and serotonin are primarily neurotransmitters involved in mood regulation and are less directly linked to the physiological stress response compared to ACTH. Thus, ACTH's central role in initiating the hormonal cascade that prepares the body for stress makes it the key hormone in the stress response.