Document Detail

The effects of pyroglutamylglutamylprolineamide, a peptide related to thyrotrophin-releasing hormone, on rat anterior pituitary cells in culture.
MedLine Citation:
PMID:  7964269     Owner:  NLM     Status:  MEDLINE    
Pyroglutamylglutamylprolineamide, which was first discovered in mammalian prostate, differs from thyrotrophin-releasing hormone (TRH) by substitution of glutamic acid for histidine at position two of the tripeptide. Recently, the newly discovered peptide has been identified in substantial concentrations in the rat anterior pituitary gland and, in this study, we have investigated the effects of the peptide on rat anterior pituitary cells in culture. GH3 cells were chosen to examine the possible effects of the new peptide, particularly in relation to its effects on the TRH receptor. This cell-type was deficient, in comparison with normal rat pituitary cells, in the new TRH-related peptide and appeared to be an ideal model cell in which to study the effects of pGlu-Glu-ProNH2. TRH (0.01-100 nM) was found to stimulate the secretion of both GH and prolactin from GH3 cells whereas pGlu-Glu-ProNH2 had no effect within the same concentration ranges. In contrast, at micromolar concentrations pGlu-Glu-ProNH2 exhibited intrinsic TRH-like activity causing stimulation of both GH and prolactin release from GH3 cells. Both TRH and pGlu-Glu-ProNH2 appeared to act through the same intracellular signalling mechanism, causing significant increases in intracellular inositol phosphate within the expected concentration ranges. However, pGlu-Glu-ProNH2 (up to 1 mM) displaced neither [3H]TRH nor [3H]MeTRH from membrane-binding sites on GH3 cells, suggesting that the effects of the new peptide were mediated through a second receptor. The physiological relevance of these effects of pGlu-Glu-ProNH2 requires further investigation.
R J Ashworth; J Ham; S M Cockle
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of endocrinology     Volume:  142     ISSN:  0022-0795     ISO Abbreviation:  J. Endocrinol.     Publication Date:  1994 Jul 
Date Detail:
Created Date:  1994-12-07     Completed Date:  1994-12-07     Revised Date:  2009-09-29    
Medline Journal Info:
Nlm Unique ID:  0375363     Medline TA:  J Endocrinol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  111-8     Citation Subset:  IM    
Department of Biochemistry & Physiology, University of Reading, Whiteknights, UK.
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MeSH Terms
Cells, Cultured
Cyclic AMP / biosynthesis
Dose-Response Relationship, Drug
Inositol Phosphates / biosynthesis
Pituitary Gland, Anterior / cytology,  drug effects*,  metabolism
Pyrrolidonecarboxylic Acid / analogs & derivatives
Rats, Sprague-Dawley
Thyrotropin-Releasing Hormone / analogs & derivatives*,  analysis,  metabolism,  pharmacology
Tumor Cells, Cultured / chemistry
Grant Support
//Wellcome Trust
Reg. No./Substance:
0/Inositol Phosphates; 24305-27-9/Thyrotropin-Releasing Hormone; 34367-54-9/thyrotropin-releasing hormone, 3-Me-; 60-92-4/Cyclic AMP; 85541-78-2/pyroglutamyl-glutamyl-proline amide; 98-79-3/Pyrrolidonecarboxylic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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