Failure of Prolactin to Inhibit Sexual Behavior in the Male Rat

Publisher Summary This chapter discusses the failure of prolactin to inhibit sexual behavior in male rat. The acute administration of dopamine (DA) receptor blockers, such as haloperidol, chlorpromazine and pimozide, suppresses copulatory behavior in the male rat. In mammals, these drugs are also very potent in increasing prolactin (Prl) release in mammals by removing the inhibitory control by DA at pituitary level. The chapter also discusses the effect on copulatory behavior of different treatments equally potent in producing hyperprolactinemia but interfering with central dopaminergic transmission to a different degree. Hyperprolactinemia was produced by the acute and chronic administration of sulpiride, a selective D 2 DA receptor blocker and domperidone, a peripheral DA receptor blocker which does not cross the blood–brain barrier. Moreover, hyperprolactinemia was produced by the chronic subcutaneous administration of Prl. In the experiment described in the chapter, male Sprague-Dawley CD R rats were used. The females used as copulatory partners were ovariectomized Sprague-Dawley CD R rats brought into heat with oestradiol and progesterone.