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Item Type: | Article |
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Title: | Elevated vascular level of ortho-tyrosine contributes to the impairment of insulin-induced arterial relaxation |
Creators Name: | Szijártó, I.A., Molnár, G.A., Mikolás, E., Fisi, V., Cseh, J., Laczy, B., Kovács, T., Böddi, K., Takátsy, A., Gollasch, M., Koller, A. and Wittmann, I. |
Abstract: | Previous studies have shown that in diabetes mellitus, insulin-induced relaxation of arteries is impaired and the level of ortho-tyrosine (o-Tyr), an oxidized amino acid is increased. Thus, we hypothesized that elevated vascular level of o-Tyr contributes to the impairment of insulin-induced vascular relaxation. Rats were fed with o-Tyr for 4 weeks. Insulin-induced vasomotor responses of isolated femoral artery were studied using wire myography. Vascular o-Tyr content was measured by HPLC, whereas immunoblot analyses were preformed to detect eNOS phosphorylation. Sustained oral supplementation of rats with o-Tyr increased the content of o-Tyr in the arterial wall and significantly reduced the relaxations to insulin. Sustained supplementation of cultured endothelial cells with o-Tyr increased the incorporation of o-Tyr and mitigated eNOS Ser (1 177) phosphorylation to insulin. Increasing arterial wall o-Tyr level attenuates insulin-induced relaxation - at least in part - by decreasing eNOS activation. Elevated level of o-Tyr could be an underlying mechanism for vasomotor dysfunction in diabetes mellitus. |
Keywords: | Insulin, Vasomotor Function, ortho-Tyrosine, eNOS, Animals, Mice, Rats |
Source: | Hormone and Metabolic Research |
ISSN: | 0018-5043 |
Publisher: | Thieme |
Volume: | 46 |
Number: | 11 |
Page Range: | 749-752 |
Date: | October 2014 |
Official Publication: | https://doi.org/10.1055/s-0034-1387701 |
PubMed: | View item in PubMed |
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