Prolactin Releasing Hormone (PRLH)

PRH mRNA was expressed in all 5 normal pituitary glands examined. In contrast, PRH mRNA was detected in only 5 of 11 human prolactinomas. All 5 prolactinomas expressing PRH were responsive to dopamine agonist treatment, whereas PRH-negative prolactinomas were non- or partially responsive.

PRH mRNA was also detected in 6 of 13 GH-secreting tumors and in 5 of 10 clinically nonfunctioning tumors investigated. PRH receptor mRNA was found in all the normal and neoplastic human pituitary samples studied. The authors concluded that the production of PRH and its receptor by normal and neoplastic pituitary tissue raises the question of whether it may regulate prolactin production in an autocrine/paracrine manner in pituitary tissue.