Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1992-6-3
pubmed:abstractText
The purpose of this study was to evaluate the contribution of endogenous GH-releasing hormone (GHRH) to exogenous GH-releasing hexapeptide (GHRP-6) activity, and to determine whether TRH or GnRH are endogenous analogs of GHRP-6. The activity of GHRP-6, a synthetic GH secretagogue, was significantly attenuated in rats administered GHRH antiserum or alpha-methyl-rho-tyrosine to reduce endogenous GHRH concentrations, and also in rats administered 5-50 micrograms/kg of [N-Ac-Tyr1,D-Arg2]-GRF 1-29 amide to block pituitary GHRH receptors. However, GHRP-6 activity was potentiated in rats administered 150 micrograms/kg [N-Ac-Tyr1,D-Arg2]-GRF 1-29 amide, presumably due to partial agonist activity of the GHRH receptor antagonist at the higher dose. These data show that endogenous GHRH contributes to full expression of exogenous GHRP-6 activity in vivo. Like TRH, a subthreshold dose of GHRP-6 was significantly more effective in hypothyroid rats than in euthyroid rats. However, suprathreshold doses of GHRP-6 were less effective in hypothyroid rats. Unlike TRH, GHRP-6 had no effect on GH and prolactin release from GH3 cells, and TRH and GnRH were poor competitors for 3H-GHRP-6 binding sites on pituitary membranes. A GnRH receptor antagonist did not block GHRP-6 activity in vivo, and GnRH administered alone or in combination with GHRP-6, did not stimulate GH release. The results of this study suggest that synergy between GHRH and GHRP-6 seen in pharmacological studies is physiologically relevant, and that TRH and GnRH are not endogenous analogs of GHRP-6.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Growth Hormone, http://linkedlifedata.com/resource/pubmed/chemical/Growth Hormone-Releasing Hormone, http://linkedlifedata.com/resource/pubmed/chemical/Hormones, http://linkedlifedata.com/resource/pubmed/chemical/Immune Sera, http://linkedlifedata.com/resource/pubmed/chemical/Methimazole, http://linkedlifedata.com/resource/pubmed/chemical/Methyltyrosines, http://linkedlifedata.com/resource/pubmed/chemical/Oligopeptides, http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Neuropeptide, http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Neurotransmitter, http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Pituitary..., http://linkedlifedata.com/resource/pubmed/chemical/Thyroxine, http://linkedlifedata.com/resource/pubmed/chemical/Triiodothyronine, http://linkedlifedata.com/resource/pubmed/chemical/alpha-Methyltyrosine, http://linkedlifedata.com/resource/pubmed/chemical/growth hormone releasing..., http://linkedlifedata.com/resource/pubmed/chemical/somatotropin releasing hormone...
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
130
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2579-86
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:1315249-Animals, pubmed-meshheading:1315249-Cell Line, pubmed-meshheading:1315249-Dose-Response Relationship, Drug, pubmed-meshheading:1315249-Female, pubmed-meshheading:1315249-Growth Hormone, pubmed-meshheading:1315249-Growth Hormone-Releasing Hormone, pubmed-meshheading:1315249-Hormones, pubmed-meshheading:1315249-Hypothyroidism, pubmed-meshheading:1315249-Immune Sera, pubmed-meshheading:1315249-Methimazole, pubmed-meshheading:1315249-Methyltyrosines, pubmed-meshheading:1315249-Oligopeptides, pubmed-meshheading:1315249-Pituitary Neoplasms, pubmed-meshheading:1315249-Rats, pubmed-meshheading:1315249-Rats, Inbred Strains, pubmed-meshheading:1315249-Receptors, Neuropeptide, pubmed-meshheading:1315249-Receptors, Neurotransmitter, pubmed-meshheading:1315249-Receptors, Pituitary Hormone-Regulating Hormone, pubmed-meshheading:1315249-Thyroid Gland, pubmed-meshheading:1315249-Thyroxine, pubmed-meshheading:1315249-Triiodothyronine, pubmed-meshheading:1315249-alpha-Methyltyrosine
pubmed:year
1992
pubmed:articleTitle
Role of selected endogenous peptides in growth hormone-releasing hexapeptide activity: analysis of growth hormone-releasing hormone, thyroid hormone-releasing hormone, and gonadotropin-releasing hormone.
pubmed:affiliation
Department of Pediatrics, University of South Florida, Tampa 33612.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't