| Central mechanisms subserving the impaired growth hormone secretion induced by persistent blockade of NMDA receptors in immature male rats. | |
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MedLine Citation:
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PMID: 1348848 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Recently, we have reported in immature female rats that short-term blockade of glutamate receptors of the N-methyl-D-aspartic acid (NMDA) subtype by the noncompetitive antagonist MK-801 induced a reduction of growth rate, basal and stimulated growth hormone (GH) release and plasma somatomedin C levels. In the present study, we investigated in immature male rats the mechanism(s) through which agonists and antagonists of glutamate receptors affect GH secretion. In 21-day-old male rats, administration of MK-801 (0.2 mg/kg i.p.b.i.d.) for 10 days induced a significant impairment of growth rate, which was unrelated to a significant reduction of food intake. GH secretion from anterior pituitary fragments of MK-801-treated rats was not significantly reduced under basal conditions but was significantly less under stimulation by 40 mM K+. Incubation of dispersed pituitary cells of 31-day-old rats with N-methyl-aspartic acid (1 and 100 microM), alone or associated with MK-801 (1 microM) did not change GH secretion. Semi quantitative densitometric analysis of hypothalami of MK-801-treated rats evidenced a clearcut decrease in the intensity of GHRH-like immuno-reactivity (LI) staining in the median eminence (ME), whereas no difference was observed in the ME-somatostatin (SS)-LI. Finally, GHRH mRNA but not SS-mRNA, evaluated by slot-blot hybridization, was reduced in the hypothalamus of MK-801-treated rats. These and our previous data would demonstrate that NMDA glutamate receptors play an important role in the neuroendocrine control of GH secretion in the rat, and suggest an action mediated by GHRH-secreting neurons. |
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Authors:
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L Cocilovo; V de Gennaro Colonna; M Zoli; G Biagini; B P Settembrini; E E Müller; D Cocchi |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Neuroendocrinology Volume: 55 ISSN: 0028-3835 ISO Abbreviation: Neuroendocrinology Publication Date: 1992 Apr |
Date Detail:
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Created Date: 1992-05-21 Completed Date: 1992-05-21 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0035665 Medline TA: Neuroendocrinology Country: SWITZERLAND |
Other Details:
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Languages: eng Pagination: 416-21 Citation Subset: IM |
Affiliation:
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Department of Pharmacology, University of Milan, Italy. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Cells, Cultured Dizocilpine Maleate / pharmacology* Gene Expression Growth Hormone / secretion* Growth Hormone-Releasing Hormone / genetics, metabolism Hypothalamus / metabolism Insulin-Like Growth Factor I / metabolism Male Pituitary Gland, Anterior / drug effects, secretion Potassium / pharmacology RNA, Messenger / metabolism Rats Rats, Inbred Strains Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors*, physiology Somatostatin / genetics, metabolism |
| Chemical | |
Reg. No./Substance:
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0/RNA, Messenger; 0/Receptors, N-Methyl-D-Aspartate; 51110-01-1/Somatostatin; 67763-96-6/Insulin-Like Growth Factor I; 7440-09-7/Potassium; 77086-22-7/Dizocilpine Maleate; 9002-72-6/Growth Hormone; 9034-39-3/Growth Hormone-Releasing Hormone |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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