Prolactin in man: a tale of two promoters

Bioessays. 2006 Oct;28(10):1051-5. doi: 10.1002/bies.20468.


The pituitary hormone prolactin (PRL) is best known for its role in the regulation of lactation. Recent evidence furthermore indicates PRL is required for normal reproduction in rodents. Here, we report on the insertion of two transposon-like DNA sequences in the human prolactin gene, which together function as an alternative promoter directing extrapituitary PRL expression. Indeed, the transposable elements contain transcription factor binding sites that have been shown to mediate PRL transcription in human uterine decidualised endometrial cells and lymphocytes. We hypothesize that the transposon insertion event has resulted in divergent (pituitary versus extrapituitary) expression of prolactin in primates, and in differential actions of pituitary versus extrapituitary prolactin in lactation versus pregnancy respectively. Importantly, the TE insertion might provide a context for some of the conflicting results obtained in studies of PRL function in mice and man.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • DNA Transposable Elements / genetics
  • Evolution, Molecular
  • Female
  • Gene Expression
  • Humans
  • Lactation / genetics
  • Mice
  • Models, Genetic
  • Pituitary Gland / metabolism
  • Pregnancy
  • Primates
  • Prolactin / genetics*
  • Promoter Regions, Genetic*
  • Transcription, Genetic


  • DNA Transposable Elements
  • Prolactin