Which hypothalamic hormone stimulates the synthesis and release of ACTH?

The hypothalamic hormone that stimulates the synthesis and release of adrenocorticotropic hormone (ACTH) is corticotropin-releasing hormone (CRH). CRH is released from the hypothalamus in response to stress and low cortisol levels, which then acts on the anterior pituitary gland to promote the secretion of ACTH. This process is essential for initiating the body's stress response and regulating the production of cortisol from the adrenal cortex.

ACTH plays a crucial role in the hypothalamic-pituitary-adrenal (HPA) axis, and its release is tightly regulated by the levels of corticosteroids in the blood, providing negative feedback to the hypothalamus and pituitary to modulate future release of CRH and ACTH. The action of CRH underscores its significance in the body's response to stress and overall endocrine regulation.

In contrast, the other hormones listed have distinct functions unrelated to the stimulation of ACTH. Thyrotropin-releasing hormone (TRH) stimulates the release of thyroid-stimulating hormone, growth hormone inhibiting hormone (GHIH) primarily inhibits growth hormone release, and gonadotropin-releasing hormone (GnRH) promotes the release of luteinizing hormone and follicle-stim