title: Cellular localization of prolactin-releasing peptide receptors in the human pituitary.
abstract: The recently identified prolactin (PRL)-releasing peptide (PrRP) is the first hypothalamic peptide hormone found to operate as a ligand of an orphan receptor that specifically stimulates PRL production from the pituitary gland. However, its other biological functions remain unknown. Using immunohistochemistry, we examined the distribution of the PrRP receptor in various human tissues, as well as the precise localization of the PrRP receptor in the human normal pituitary. Among various tissues examined, PrRP receptor-immunopositive cells were detected only in the pituitary gland. A double immunohistochemical procedure was used to examine PrRP receptor-positive cells from ten normal human pituitary glands, and it was determined that numerous PrRP receptor-positive cells are also positive for adrenocorticotropic hormone (ACTH) but negative for PRL. Growth hormone-, beta-thyroid-stimulating hormone-, beta-follicle-stimulating hormone-, beta-luteinizing hormone- or alpha-subunit-positive cells did not test positive for the presence of PrRP receptors. Thus, we suggest that PrRP receptor and probably PrRP may play a regulatory role in ACTH secretion, rather than in the release of PRL from the human anterior pituitary. This is the first report to demonstrate colocalization of the PrRP receptor and ACTH by immunohistochemistry.
authors.affiliation: Department of Neurosurgery, Showa University School of Medicine, 5-8 Hatanodai 1, Shinagawa-ku, 142-8666, Tokyo, Japan. takumi@med.showa-u.ac.jp
authors.forename: Takumi
authors.initials: T
authors.lastname: Abe
authors.forename: Natsumi
authors.initials: N
authors.lastname: Koga
authors.forename: Motowo
authors.initials: M
authors.lastname: Tomita
authors.forename: Takahiko
authors.initials: T
authors.lastname: Tonoike
authors.forename: Miki
authors.initials: M
authors.lastname: Kushima
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Takahashi
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Sano
authors.forename: Matsuo
authors.initials: M
authors.lastname: Taniyama
mesh_terms: D000818:Animals; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007150:Immunohistochemistry; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000378:metabolism; D010446:Peptide Fragments / Q000276:immunology* / Q000378:metabolism; D010902:Pituitary Gland / Q000166:cytology / Q000378:metabolism*; D010907:Pituitary Hormones / Q000378:metabolism; D011817:Rabbits; D018013:Receptors, Neuropeptide / Q000276:immunology / Q000378:metabolism*
chemical_list: D010446:Peptide Fragments; D010907:Pituitary Hormones; D018013:Receptors, Neuropeptide; C400801:receptor, prolactin-releasing peptide