Human growth hormone is secreted by which gland?

• A. Pituitary gland
• B. Thyroid gland
• C. Adrenal gland
• D. Pineal gland

Answer: (A)

The key idea is identifying where growth hormone originates. Growth hormone is produced by the anterior part of the pituitary gland, specifically by somatotroph cells in the adenohypophysis, in response to releasing signals from the hypothalamus. The hypothalamus sends growth hormone-releasing hormone to stimulate its secretion and somatostatin to dampen it, and the hormone then travels through the bloodstream to act on various tissues (notably the liver to produce IGF-1) to promote growth and metabolism. The other glands listed have different roles: the thyroid gland produces thyroid hormones, the adrenal gland releases cortisol and catecholamines, and the pineal gland makes melatonin. So the pituitary gland is the source of human growth hormone.