Effects of acute and long-term domperidone treatment on prolactin and gonadal hormone levels and sexual behavior of male and female rats

Domperidone (DOMP), a dopamine D-2 blocker that is unable to cross the blood-brain barrier, is an experimental tool used to induce hyperprolactinemia. Acute and long-term DOMP administration was tested in male and female rats for its effects on sexual behavior and plasma gonadal hormone levels. DOMP (4.0 mg/kg) was injected IP either acutely or daily for 30 days. Acute treatment failed to modify any behavioral parameter observed. The 5-day treatment stimulated and the 30-day treatment failed to inhibit sexual behavior of male rats. Serum testosterone levels were significantly reduced after 30 days of treatment in male rats. The 30-day treatment also inhibited sexual behavior and enhanced plasma progesterone levels in ovariectomized and intact female rats, respectively. The present results may be due to DOMP-induced long-term hyperprolactinemia. Alternatively, blockade of dopamine peripheral receptors induced by this treatment may also be responsible for the behavioral changes reported here. Moreover, these data suggest that female rats are more susceptible than males to the behavioral effects of long-term hyperprolactinemia. (C) 1997 Elsevier Science Inc.