Prolactin secretion following repetitive seizures.

We studied serum prolactin levels after 24 seizures occurring in eight subjects. Video-EEG intracranial monitoring confirmed temporal or frontal partial seizures. Seizure type, focus, and duration were similar for seizures with and without significant postictal prolactin elevations. The seizure-free interval (the time between seizures) varied considerably. Seizures occurring after longer seizure-free intervals (31.75 to 240 hours) showed robust prolactin responses. After shorter seizure-free intervals (1.07 to 25.42 hours), prolactin responses were reduced. This suggests that the amount of releasable prolactin is limited, depleted by seizures, or perhaps inhibited by prolactin feedback. Seizure-free intervals should be considered when interpreting prolactin levels.