Abe Takumi, Koga Natsumi, Tomita Motowo, Tonoike Takahiko, Kushima Miki, Takahashi Katsuhiko, Sano Yoshihiko, Taniyama Matsuo
Department of Neurosurgery, Showa University School of Medicine, 5-8 Hatanodai 1, Shinagawa-ku, 142-8666, Tokyo, Japan.
Acta Neuropathol. 2003 Nov;106(5):495-500. doi: 10.1007/s00401-003-0753-7. Epub 2003 Aug 12.
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.
