title: Prolactin: fishy tales of its primary regulator and function.
abstract: Prolactin (PRL) is an important regulator of multiple biological functions, and the control of PRL expression integrates a wide spectrum of molecules throughout vertebrates. PRL-releasing peptide (PrRP) seems to be an essential stimulator of PRL transcription and secretion in teleost pituitary and peripheral organs. In the amphibious euryhaline mudskipper, the localization of mRNA levels of PrRP and PRL as well as their regulation during acclimation to different environments are closely related. The presence of PrRP-PRL axes in the peripheral organs might suggest an ancient history of this axis prior to the evolution of the hypothalamus-pituitary, and it is possible that the PrRP is an original and primary regulator of PRL. In the euryhaline fishes, the permeability of gut of seawater-acclimated fish is generally greater than that of the freshwater (FW)-acclimated fish. The modification in the epithelial cell renewal system may play an important role in regulation of the permeability. PRL induces the cell proliferation during FW acclimation, whereas cortisol stimulates both cell proliferation and apoptosis. Indeed, a large proportion of the various actions of PRL seem to be associated directly or indirectly with cell proliferation and/or apoptosis, which might be a primary function of PRL.
authors.affiliation: Ushimado Marine Laboratory, Faculty of Science, Okayama University, Setouchi, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Aiko
authors.initials: A
authors.lastname: Oda
authors.forename: Kenji
authors.initials: K
authors.lastname: Narita
authors.forename: Hideya
authors.initials: H
authors.lastname: Takahashi
authors.forename: Takuji
authors.initials: T
authors.lastname: Oda
authors.forename: Jun
authors.initials: J
authors.lastname: Fujiwara
authors.forename: Waichiro
authors.initials: W
authors.lastname: Godo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005399:Fishes / Q000502:physiology*; D006801:Humans; D008969:Molecular Sequence Data; D011388:Prolactin / Q000378:metabolism / Q000502:physiology*; D013973:Thyrotropin-Releasing Hormone / Q000378:metabolism / Q000502:physiology
chemical_list: D013973:Thyrotropin-Releasing Hormone; D011388:Prolactin