Elevation of serum prolactin acutely after administration of p-chloroamphetamine in rats

p-Chloroamphetamine hydrochloride (0.5-10 mg/kg, i.p.) caused a rapid (within 30 minutes), dose-related increase in serum prolactin concentration in male rats. The effect was antagonized by pretreatment with p-chlorophenylalanine, an inhibitor of serotonin synethesis, or by metergoline, a serotonin receptor antagonist. The acute elevation of serum prolactin may have been mediated by the release of serotonin by p-chloroamphetamine.