Question

Which of the following statement is correct regarding hypothalamic control of pituitary function ?

• A. All the hypothalamic hormones are synthesised and secreted by neurons
• B. Blood flows from the anterior pituitary to the hypothalamus in the portal vessels
• C. The hypothalamic releasing hormones reach the general circulation in significant amounts
• D. Loss of dopaminergic neurons in the hypothalamus is likely to lead to a fall in the secretion of prolactin

Answer 1

The correct option is A All the hypothalamic hormones are synthesised and secreted by neurons

Hormones released by the hypothalamus, originate in the hypothalamic neurons, pass through axons and are released from their nerve endings into the portal circulatory system through which, the hormones reach the pituitary gland.
Blood flows from the hypothalamus to the anterior pituitary gland via the hypothalamo-hypophyseal portal system. Although the releasing hormones are secreted into the portal system, negligible quantities reach the general circulation.
Dopamine acts as an inhibitory hormone on the pituitary lactotrophs that secrete prolactin.