The posterior pituitary gland during pregnancy continues to produce which substances?

• A. Oxytocin and AVP
• B. Melatonin and dopamine
• C. Growth hormone and prolactin
• D. TSH and ACTH

Answer: (A)

The posterior pituitary releases two hormones that are actually made by hypothalamic neurons: oxytocin and vasopressin (AVP). It stores and releases these in response to neural signals, rather than synthesizing them itself. In pregnancy, these hormones continue to be secreted to support maternal and fetal physiology. Oxytocin promotes uterine contractions and the milk-ejection reflex, which are crucial during labor and after birth. Vasopressin helps regulate the mother’s water balance and vascular tone, supporting circulatory stability. The other substances listed come from different sources: melatonin is produced by the pineal gland, dopamine is a brain neurotransmitter, growth hormone and prolactin come from the anterior pituitary, and TSH and ACTH are also produced by the anterior pituitary.