Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2003-6-6
pubmed:abstractText
Insulin and leptin act in the hypothalamus, providing robust anorexigenic signals. The exposure of homeothermic animals to a cold environment leads to increased feeding, accompanied by sustained low levels of insulin and leptin. In the present study, the initial and intermediate steps of the insulin-signaling cascade were evaluated in the hypothalamus of cold-exposed Wistar rats. By immunohistochemistry, most insulin receptor (IR) and insulin receptor substrate-2 (IRS-2) immunoreactivity localized to the arcuate nucleus. Basal levels of tyrosine phosphorylation of IR and IRS-2 were increased in cold-exposed rats compared with rats maintained at room temperature. However, after an acute, peripheral infusion of exogenous insulin, significantly lower increases of IR and IRS-2 tyrosine phosphorylation were detected in the hypothalamus of cold-exposed rats. Insulin-induced association of p85/phosphatidylinositol 3-kinase with IRS-2, Ser473 phosphorylation of Akt, and tyrosine phosphorylation of ERK was significantly reduced in the hypothalamus of cold-exposed rats. To test the hypothesis of functional impairment of insulin signaling in the hypothalamus, intracerebroventricularly cannulated rats were acutely treated with insulin, and food ingestion was measured over a period of 12 h. Cold-exposed animals presented a significantly lower insulin-induced reduction in food consumption compared with animals maintained at room temperature. Hence, the present studies reveal that animals exposed to cold are resistant, both at the molecular and the functional level, to the actions of insulin in the hypothalamus.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0193-1849
pubmed:author
pubmed:issnType
Print
pubmed:volume
285
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
E216-23
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed-meshheading:12644444-Animals, pubmed-meshheading:12644444-Blood Glucose, pubmed-meshheading:12644444-Cold Temperature, pubmed-meshheading:12644444-Eating, pubmed-meshheading:12644444-Fatty Acids, Nonesterified, pubmed-meshheading:12644444-Hormones, pubmed-meshheading:12644444-Hypoglycemic Agents, pubmed-meshheading:12644444-Hypothalamus, pubmed-meshheading:12644444-Immunoblotting, pubmed-meshheading:12644444-Injections, Intraventricular, pubmed-meshheading:12644444-Insulin, pubmed-meshheading:12644444-Insulin Resistance, pubmed-meshheading:12644444-Male, pubmed-meshheading:12644444-Mitogen-Activated Protein Kinases, pubmed-meshheading:12644444-Phosphorylation, pubmed-meshheading:12644444-Precipitin Tests, pubmed-meshheading:12644444-Rats, pubmed-meshheading:12644444-Rats, Wistar, pubmed-meshheading:12644444-Satiety Response, pubmed-meshheading:12644444-Serine, pubmed-meshheading:12644444-Signal Transduction, pubmed-meshheading:12644444-Tyrosine
pubmed:year
2003
pubmed:articleTitle
Molecular and functional resistance to insulin in hypothalamus of rats exposed to cold.
pubmed:affiliation
Department of Internal Medicine, State University of Campinas, Brazil.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't