[Action mechanisms of prolactin and its receptors on penile erection and ejaculation].

Prolactin is a polypeptide hormone which mainly acts on the reproductive system and plays an important role in penile erection and ejaculation. Prolactin receptors have a variety of short forms apart from the classic long form, which are widely expressed in male reproductive glands. High levels of prolactin can induce erectile dysfunction and results in secondary male infertility, which are mainly associated with the inhibition of dopaminergic activity, reduction of the testosterone level, and contraction of the cavernous smooth muscle. Moreover, low levels of prolactin can result in ejaculatory dysfunction. This article updates the views on the expressions of prolactin receptors in the male reproductive system, the effects of prolactin on penile erection and ejaculation, and its action mechanisms.