Final answer:
Antipsychotic medications elevate prolactin levels by blocking dopamine receptors, which inhibits the release of prolactin.
Step-by-step explanation:
Antipsychotic medications can elevate prolactin (PRL) levels by blocking dopamine receptors in the brain. Dopamine normally inhibits prolactin release, so when the dopamine receptors are blocked, the inhibition is lifted and prolactin levels increase. For example, antipsychotics like risperidone antagonize D2 receptors and serotonin type 2 receptors. By blocking D2 receptors, they prevent dopamine from inhibiting prolactin release, resulting in elevated prolactin levels. This increase in prolactin can lead to side effects such as breast enlargement, milk production, and irregular menstrual periods in both males and females.