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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
1
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pubmed:dateCreated |
1995-6-2
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pubmed:abstractText |
Administration of exogenous glucocorticoids is known to suppress the HPA axis and has been reported to occupy brain glucocorticoid receptors, eventually leading to down-regulation. To determine the effects of chronic corticosterone administration on HPA axis function, corticosterone was administered as both 25% and 50% corticosterone/cholesterol pellets. Rats were sacrificed 6 days after corticosterone pellet implantation. The 25% corticosterone pellets produced a small increase in morning corticosterone concentrations but no change in evening ACTH or corticosterone secretion. The 50% corticosterone pellets produced constant corticosterone concentrations of 5-6 micrograms/dl, with no circadian variation in corticosterone, indicating inhibition of evening ACTH and corticosterone secretion. The 25% corticosterone pellets produced no significant decrease in thymus weight or in adrenal weight; 50% corticosterone pellets produced significant decreases in thymus weight and adrenal weight. Neither 25% nor 50% corticosterone pellets produced significant decreases in GR in hippocampus and cortex. The 50% corticosterone pellets treatment resulted in a decrease in anterior pituitary POMC mRNA levels, a decrease in baseline and oCRH stimulated ACTH release from the anterior pituitary, and a near complete inhibition of the AM and PM response to restraint stress. These results suggest that: 1) the HPA axis was able to adjust to the small increase in glucocorticoids produced by the 25% cort pellets with minimal disturbances in function and 2) 50% corticosterone pellets exert a significant inhibitory effect on stress and diurnal ACTH secretion which appears to be exerted at the pituitary as well as possible inhibitory effects on brain.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Adrenocorticotropic Hormone,
http://linkedlifedata.com/resource/pubmed/chemical/Biological Markers,
http://linkedlifedata.com/resource/pubmed/chemical/Corticosterone,
http://linkedlifedata.com/resource/pubmed/chemical/Dexamethasone,
http://linkedlifedata.com/resource/pubmed/chemical/Drug Implants,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Glucocorticoid
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pubmed:status |
MEDLINE
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pubmed:month |
Jan
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pubmed:issn |
0953-8194
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
7
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
37-45
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:7735296-Adrenalectomy,
pubmed-meshheading:7735296-Adrenocorticotropic Hormone,
pubmed-meshheading:7735296-Animals,
pubmed-meshheading:7735296-Biological Markers,
pubmed-meshheading:7735296-Corticosterone,
pubmed-meshheading:7735296-Dexamethasone,
pubmed-meshheading:7735296-Down-Regulation,
pubmed-meshheading:7735296-Drug Implants,
pubmed-meshheading:7735296-Feedback,
pubmed-meshheading:7735296-Hypothalamo-Hypophyseal System,
pubmed-meshheading:7735296-Male,
pubmed-meshheading:7735296-Pituitary-Adrenal System,
pubmed-meshheading:7735296-Radioimmunoassay,
pubmed-meshheading:7735296-Rats,
pubmed-meshheading:7735296-Rats, Sprague-Dawley,
pubmed-meshheading:7735296-Receptors, Glucocorticoid
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pubmed:year |
1995
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pubmed:articleTitle |
Negative feedback regulation following administration of chronic exogenous corticosterone.
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pubmed:affiliation |
Mental Health Research Institute, University of Michigan, Ann Arbor 48109, USA.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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