Which hypothalamic releasing hormone stimulates growth hormone release from the anterior pituitary?

• A. Gonadotropin RH
• B. Corticotrophin RH
• C. Thyrotropin RH
• D. Growth Hormone-Releasing Hormone

Answer: (D)

The question tests how the hypothalamus controls the anterior pituitary using releasing hormones. Growth Hormone-Releasing Hormone (GHRH) is the signal that tells the pituitary’s somatotrophs to release growth hormone. When GHRH binds its receptor on these cells, it activates a signaling pathway (involving cAMP) that ramps up production and secretion of growth hormone into the bloodstream.

Other releasing hormones listed have different targets: Gonadotropin-releasing hormone stimulates LH and FSH; corticotrophin-releasing hormone stimulates ACTH; and thyrotropin-releasing hormone stimulates TSH (and can affect prolactin). Somatostatin, not listed, inhibits growth hormone release. Since the prompt asks which hormone specifically stimulates GH release, Growth Hormone-Releasing Hormone is the correct choice.