Prolactin release is a systemic effect of activation of which receptor?

Prolactin release is a systemic effect of activation of which receptor?

• A. Mu receptor
• B. Delta receptor
• C. Kappa receptor
• D. All three

Answer: (A)

Prolactin release is driven by removal of dopamine’s inhibitory brake. Dopamine from hypothalamic tuberoinfundibular neurons normally acts on D2 receptors on pituitary lactotrophs to suppress prolactin secretion. Activation of mu opioid receptors in the hypothalamus inhibits these dopaminergic neurons, reducing dopamine release into the pituitary portal system and thereby lifting the inhibition. The result is increased prolactin release into the bloodstream. While delta and kappa receptors can affect various neuroendocrine pathways, the robust, well-established route for systemic prolactin rise is via mu receptor–mediated inhibition of hypothalamic dopamine.

Prolactin release is driven by removal of dopamine’s inhibitory brake. Dopamine from hypothalamic tuberoinfundibular neurons normally acts on D2 receptors on pituitary lactotrophs to suppress prolactin secretion. Activation of mu opioid receptors in the hypothalamus inhibits these dopaminergic neurons, reducing dopamine release into the pituitary portal system and thereby lifting the inhibition. The result is increased prolactin release into the bloodstream. While delta and kappa receptors can affect various neuroendocrine pathways, the robust, well-established route for systemic prolactin rise is via mu receptor–mediated inhibition of hypothalamic dopamine.