title: Pyroglutamylglutamylprolineamide is present in rat anterior and posterior pituitary gland.
abstract: A new TRH-like peptide pyroglutamylglutamylprolineamide (pGlu-Glu-ProNH2) has recently been purified and characterized from both the rabbit prostate complex and human semen. In this study, TRH-immunoreactive peptides were extracted from anterior pituitary, posterior pituitary and hypothalamus and subjected to gel exclusion chromatography. For each tissue, TRH was resolved from pGlu-Glu-ProNH2 by anion-exchange chromatography at pH 7.6. In the anterior pituitary, 63% of the TRH immunoreactivity was chromatographically identical to pGlu-Glu-ProNH2 whereas in the posterior pituitary the new peptide represented less than 5% of the total TRH immunoreactivity. Only trace levels of pGlu-Glu-ProNH2 were observed in hypothalamus, suggesting that the acidic TRH-related peptide found in the anterior pituitary may not be of hypothalamic origin. The new TRH-like peptide was purified from whole pituitaries by gel exclusion and ion-exchange chromatography, followed by high power liguid chromatography and was shown to have chromatographic properties identical to pGlu-Glu-ProNH2. Amino acid analysis of the purified peptide revealed glutamic acid and proline residues in the ratio Glx:2 Pro:1, which is the expected composition of pGlu-Glu-ProNH2 after acid hydrolysis.
authors.affiliation: Department of Biochemistry & Physiology, University of Reading, Whiteknights, London.
authors.forename: R J
authors.initials: RJ
authors.lastname: Ashworth
authors.forename: J M
authors.initials: JM
authors.lastname: Morrell
authors.forename: A
authors.initials: A
authors.lastname: Aitken
authors.forename: Y
authors.initials: Y
authors.lastname: Patel
authors.forename: S M
authors.initials: SM
authors.lastname: Cockle
mesh_terms: D000818:Animals; D002850:Chromatography, Gel; D005260:Female; D007031:Hypothalamus / Q000737:chemistry; D009842:Oligopeptides / Q000032:analysis*; D010903:Pituitary Gland, Anterior / Q000737:chemistry*; D010904:Pituitary Gland, Posterior / Q000737:chemistry*; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D051381:Rats; D011919:Rats, Inbred Strains; D013973:Thyrotropin-Releasing Hormone / Q000031:analogs & derivatives*
chemical_list: D009842:Oligopeptides; D013973:Thyrotropin-Releasing Hormone; C059697:pyroglutamyl-glutamyl-proline amide; D011761:Pyrrolidonecarboxylic Acid