Prolactin message in brain and pituitary of adult male rats is identical: PCR cloning and sequencing of hypothalamic prolactin cDNA from intact and hypophysectomized adult male rats.

Prolactin (PRL), or a PRL-like molecule has been identified in the central nervous system and other tissues by numerous investigators. The previous finding of PRL in brain persisting for weeks following hypophysectomy led us, and others, to conclude the brain and central nervous system PRL is synthesized locally. Also, our previous results showing PRL mRNA in hypothalamic and extra-hypothalamic brain regions using reverse transcription-polymerase chain reaction (RT-PCR) techniques, along with this report that the sequence of the PRL message in the brain is identical to that found in the anterior pituitary solidifies our, and others, hypothesis that PRL is synthesized in many locations other than the traditional one (anterior pituitary). The actual sequencing of hypothalamic PRL cDNA produced from RT-PCR of mRNA from intact or hypophysectomized rats demonstrates unequivocally that brain PRL mRNA is identical to anterior pituitary prolactin mRNA.