Which hormone is stored and released by the posterior pituitary and is derived from neural ectoderm?

• A. Vasopressin
• B. Growth hormone
• C. Prolactin
• D. Adrenocorticotropic hormone

Answer: (A)

The posterior pituitary is neural tissue that stores and releases hormones produced by hypothalamic neurons, and it is derived from neural ectoderm. Among the hormones released from the posterior pituitary, vasopressin (antidiuretic hormone) is stored there after being synthesized in hypothalamic neurons and transported down their axons to the neurohypophysis, where it is stored and later released in response to neural signals. This contrasts with the anterior pituitary hormones listed, which are produced in the anterior lobe from oral ectoderm. Vasopressin’s role in increasing water reabsorption in the kidney explains why it’s stored and released from the posterior pituitary.