Question:easy
Prolactin secretion will be inhibited by
Prolactin secretion will be inhibited by
Show Hint
Dopamine is the hypothalamic prolactin inhibiting factor, acting on D2 receptors of lactotrophs.
Updated On: Jul 8, 2026
- Haloperidol
- GABA
- Neurophysin
- Dopamine
Show Solution
The Correct Option is D
Solution and Explanation
Step 1: Recall the unusual control of prolactin.
Most anterior pituitary hormones are switched on by a hypothalamic releasing hormone, but prolactin is different, it is mainly kept switched off by an inhibiting factor.
Step 2: Name the inhibiting factor.
This prolactin inhibiting factor is dopamine, made by neurons in the hypothalamus and carried to the pituitary through the hypophyseal portal vessels.
Step 3: See how it works.
Dopamine attaches to D2 receptors on the lactotroph cells of the anterior pituitary and keeps prolactin release turned down. If dopamine signaling drops, for example when a drug blocks its receptor, prolactin rises instead.
Step 4: Check the other options against this logic.
Haloperidol blocks dopamine receptors, so it raises prolactin, the opposite of what the question asks. GABA is not the recognized prolactin inhibiting factor. Neurophysin only carries oxytocin and vasopressin, it has nothing to do with prolactin.
Step 5: Conclude.
The hormone that inhibits prolactin secretion is dopamine.
\[ \boxed{\text{Dopamine}} \]
Most anterior pituitary hormones are switched on by a hypothalamic releasing hormone, but prolactin is different, it is mainly kept switched off by an inhibiting factor.
Step 2: Name the inhibiting factor.
This prolactin inhibiting factor is dopamine, made by neurons in the hypothalamus and carried to the pituitary through the hypophyseal portal vessels.
Step 3: See how it works.
Dopamine attaches to D2 receptors on the lactotroph cells of the anterior pituitary and keeps prolactin release turned down. If dopamine signaling drops, for example when a drug blocks its receptor, prolactin rises instead.
Step 4: Check the other options against this logic.
Haloperidol blocks dopamine receptors, so it raises prolactin, the opposite of what the question asks. GABA is not the recognized prolactin inhibiting factor. Neurophysin only carries oxytocin and vasopressin, it has nothing to do with prolactin.
Step 5: Conclude.
The hormone that inhibits prolactin secretion is dopamine.
\[ \boxed{\text{Dopamine}} \]
Was this answer helpful?
0
