Prolactin (PRL ) , a protein hormone, a weight of about 23kD , is synthesized mainly in the pituitary cells , but also other cells in the body can produce the hormone . Pituitary laktotrofy exhibit morphological and functional heterogeneity according to sex , and synthesized PRL undergoes post-translational modifications of many . PRL and its molecular variants can contribute to various biological processes , and the secretion of this hormone is regulated by a variety of stimulating and inhibitory factors . In the male reproductive system PRL not only affects the morphology and function of the nucleus, but also the epididymis , seminal vesicles , prostate and sperm. PRL can act directly through its receptors located in these organs as well as indirectly via influence on the release of gonadotropins and testosterone . The structure and location of the PRL receptors in organs of the male reproductive system , and the action of the hormone in these organs following hyperprolactinemia . Although a well-established and proven mechanism of action of PRL in the female reproductive system impact of this hormone on the male reproductive system has not been elucidated yet and needs further investigation.