Expression of Guanylin in "Pars Tuberalis-Specific Cells" and Gonadotrophs of Rat Adenohypophysis

• Published in: Proceedings of the National Academy of Sciences - PNAS 2000-02, Vol.97 (3), p.1131-1136
• Main Authors: D'Este, Loredana, Kulaksiz, Hasan, Rausch, Ulrich, Vaccaro, Rosa, Wenger, Tibor, Tokunaga, Yoshimitsu, Renda, Tindaro G., Cetin, Yalcin
• Format: Article
• Language: English
• Subjects: adenohypophysis; Animals; Anterior pituitary; Biological Sciences; Blood vessels; Cells; Cellular biology; Complementary DNA; Duodenum; Endocrine cells; Epithelial cells; Female; Gastrointestinal Hormones; Gels; guanylin; hypothalamo-hypophyseal system; Hypothalamo-Hypophyseal System - physiology; Male; Microscopy, Immunoelectron; Natriuretic Peptides; Peptides; Peptides - genetics; Peptides - metabolism; Pituitary gland; Pituitary Gland, Anterior - metabolism; Pituitary Gland, Anterior - ultrastructure; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; Rodents; Subcellular Fractions - metabolism; Water-Electrolyte Balance - physiology
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.97.3.1131

The intestinal peptide guanylin regulates the electrolyte/water transport in the gastrointestinal epithelium by paracrine/luminocrine mechanisms. Because guanylin also circulates in the blood, we investigated the rat hypothalamo-pituitary region for expression and cellular localization of this peptide. Reverse transcriptase-PCR analyses with guanylin-specific primers revealed expression of the peptide in the pars tuberalis and pars distalis of the pituitary. Western blotting analyses in hypophyseal tissue extracts identified the expected 12.5-kDa immunoreactive peptide by using two different region-specific guanylin antisera. Light and electron microscopic immunocytochemistry with the same antisera localized guanylin in "pars tuberalis-specific cells" in the juxtaneural pars tuberalis adjacent to nerve endings and blood vessels of the hypothalamo-pituitary portal system and in gonadotrophic cells within the distal pars tuberalis and ventrolateral part of the pars distalis. The presence and cell-specific localization of guanylin within the hypothalamo-hypophyseal system indicate that this peptide may be specifically involved in paracrine and endocrine regulatory mechanisms.