Abstract
The effects of chlorpromazine (CPZ) and estradiol benzoate (EB) on serum prolactin (PRL) levels were studied in gonadectomized male and female rats. In both sexes CPZ (25mg/kg body weight) produced an elevation of PRL when measured 2hr after the injection, but the elevated levels were higher in ovariectomized rats than in orchidectomized rats. These results reconfirm a sexual difference in the regulatory mechanism of PRL secretion in response to the dopamine receptor blocker. Pretreatment with 5μg EB 48hr before CPZ injection abolished this sexual difference in serum PRL concentration.