Which pathway, when dopamine is low, leads to increased prolactin levels?

Which pathway, when dopamine is low, leads to increased prolactin levels?

• A. Tuberoinfundibular pathway
• B. Nigrostriatal pathway
• C. Mesolimbic pathway
• D. Mesocortical pathway

Answer: (A)

Dopamine normally inhibits prolactin release from pituitary lactotrophs via the tuberoinfundibular pathway. When dopamine levels fall—or when D2 receptors in this pathway are blocked—this inhibition is lifted, leading to increased prolactin secretion. The extra prolactin can cause symptoms like galactorrhea and amenorrhea. The other pathways—nigrostriatal, mesolimbic, and mesocortical—are not major regulators of prolactin.

Dopamine normally inhibits prolactin release from pituitary lactotrophs via the tuberoinfundibular pathway. When dopamine levels fall—or when D2 receptors in this pathway are blocked—this inhibition is lifted, leading to increased prolactin secretion. The extra prolactin can cause symptoms like galactorrhea and amenorrhea. The other pathways—nigrostriatal, mesolimbic, and mesocortical—are not major regulators of prolactin.