Linked Life Data

16513828

Source:http://linkedlifedata.com/resource/pubmed/id/16513828

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2006-5-18
pubmed:abstractText
There is a negative relationship between obesity and GH. However, it is not known how metabolic changes, associated with obesity, lead to a reduction in GH output. This study examined the GH axis of two mouse models of obesity, the leptin-deficient (ob/ob) mouse and the diet-induced obese (DIO; high-fat fed) mouse. Both models displayed hyperglycemia and hyperinsulinemia with reduced expression of GH as well as reduced expression of pituitary receptors important for GH synthesis and release [GHRH receptor (DIO only) and the ghrelin receptor (ob/ob and DIO)]. These pituitary changes were not accompanied by changes in hypothalamic expression of GHRH or somatostatin; suggesting that alterations in pituitary function may be precipitated in part by direct effects of systemic signals. Of the metabolic and hormonal parameters examined (insulin, glucose, corticosterone, free fatty acids, ghrelin, and IGF-I), only insulin/glucose showed a significant, and negative, correlation with pituitary expression. Pituitaries of DIO mice remained responsive to the acute in vivo actions of insulin, as assessed by phosphorylation of Akt, despite systemic (skeletal muscle and fat) insulin resistance. In addition, treating primary pituitary cell cultures from lean mice with insulin reduced GH release as well as GH, GHRH receptor, and ghrelin receptor mRNA levels compared with vehicle-treated controls, where the magnitude of suppression of pituitary mRNA levels was similar to that observed in the DIO mouse. These results coupled with the fact that the pituitary expresses the insulin receptor at levels comparable to tissues classically considered insulin sensitive, indicates high circulating insulin levels can directly contribute to the suppression of GH synthesis and release in the obese state.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
147
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2754-63
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Impact of obesity on the growth hormone axis: evidence for a direct inhibitory effect of hyperinsulinemia on pituitary function.
pubmed:affiliation
Section of Endocrinology and Metabolism, Department of Medicine, University of Illinois at Chicago, Illinois, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural