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 .