This Review will answer your question,

https://www.omicsonline.org/open-access/the-role-of-prolactin-in-men-2161-1017-1000222.php?aid=66774

In humans, prolactin is produced at least in the anterior pituitary, decidua, myometrium, breast, lymphocytes, leukocytes and prostate.

Pituitary PRL is controlled by the Pit-1 transcription factor that binds to the prolactin gene at several sites. Ultimately dopamine, extrapituitary PRL is controlled by a superdistal promoter and apparently unaffected by dopamine.. The thyrotropin-releasing hormone and the vasoactive intestinal peptide stimulate the secretion of prolactin in experimental settings, however their physiological influence is unclear. The main stimulus for prolactin secretion is suckling, the effect of which is neuronally mediated.[32] A key regulator of prolactin production is estrogens that enhance growth of prolactin-producing cells and stimulate prolactin production directly, as well as suppressing dopamine.

Physiologic levels of prolactin in males enhance luteinizing hormone-receptors in Leydig cells, resulting in testosterone secretion, which leads to spermatogenesis.