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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2004-11-19
pubmed:abstractText
Previously, using an animal model of syndrome X, the obese Zucker rat (OZR), we documented impaired endothelium-dependent vasodilation. The aim of this study was to determine whether reduced expression or altered posttranslational regulation of endothelial nitric oxide synthase (eNOS) underlies the vascular dysfunction in OZR rats. There was no significant difference in the relative abundance of eNOS in hearts, aortas, or skeletal muscle between lean Zucker rats (LZR) and OZR regardless of age. There was no difference in eNOS mRNA levels, as determined by real-time PCR, between LZR and OZR. The inability of insulin resistance to modulate eNOS expression was also documented in two additional in vivo models, the ob/ob mouse and the fructose-fed rat, and in vitro via adenoviral expression of protein tyrosine phosphatase 1B in endothelial cells. We next investigated whether changes in the acute posttranslational regulation of eNOS occurs with insulin resistance. Phosphorylation of eNOS at S632 (human S633) and T494 was not different between LZR and OZR; however, phosphorylation of S1176 was significantly enhanced in OZR. Phosphorylation of S1176 was not different in the ob/ob mouse or in fructose-fed rats. The association of heat shock protein 90 with eNOS, a key regulatory step controlling nitric oxide and aberrant O2- production, was not different between OZR and LZR. Taken together, these results suggest that changes in eNOS expression or posttranslation regulation do not underlie the vascular dysfunction seen with insulin resistance and that other mechanisms, such as altered localization, reduced availability of cofactors, substrates, and the elevated production of O2-, may be responsible.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0363-6135
pubmed:author
pubmed:issnType
Print
pubmed:volume
287
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
H2384-93
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Insulin resistance does not diminish eNOS expression, phosphorylation, or binding to HSP-90.
pubmed:affiliation
Vascular Biology Center, Medical College of Georgia, 1459 Laney Walker Blvd., Augusta, GA 30912, USA. dfulton@mcg.edu
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't