Hyperprolactinemia is associated with D2 occupancy in what range?

Hyperprolactinemia is associated with D2 occupancy in what range?

• A. 10-30%
• B. 50-75%
• C. 78%
• D. 90-100%

Answer: (B)

Dopamine acting at D2 receptors on pituitary lactotrophs normally keeps prolactin levels in check. When a drug blocks these receptors, prolactin rises, and the amount of receptor occupancy needed to see this rise is around half to three-quarters. So, a D2 occupancy roughly in the 50-75% range is what tends to produce hyperprolactinemia. Occupancies much lower generally don’t push prolactin up, while higher occupancies (especially well above 75%) are more likely to cause extrapyramidal symptoms as well.

Dopamine acting at D2 receptors on pituitary lactotrophs normally keeps prolactin levels in check. When a drug blocks these receptors, prolactin rises, and the amount of receptor occupancy needed to see this rise is around half to three-quarters. So, a D2 occupancy roughly in the 50-75% range is what tends to produce hyperprolactinemia. Occupancies much lower generally don’t push prolactin up, while higher occupancies (especially well above 75%) are more likely to cause extrapyramidal symptoms as well.