Elevated vascular level of ortho -Tyrosine contributes to the impairment of insulin-induced arterial relaxation

I. A. Szijártó, G. A. Molnár, E. Mikolás, V. Fisi, J. Cseh, B. Laczy, T. Kovács, K. Böddi, A. Takátsy, M. Gollasch, A. Koller, I. Wittmann

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6 Citations (Scopus)

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

Original languageEnglish
Pages (from-to)749-752
Number of pages4
JournalHormone and Metabolic Research
Volume46
Issue number11
DOIs
Publication statusPublished - Oct 2014

Keywords

  • eNOS
  • insulin
  • ortho -tyrosine
  • vasomotor function

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Biochemistry
  • Endocrinology
  • Clinical Biochemistry
  • Biochemistry, medical

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    Szijártó, I. A., Molnár, G. A., Mikolás, E., Fisi, V., Cseh, J., Laczy, B., Kovács, T., Böddi, K., Takátsy, A., Gollasch, M., Koller, A., & Wittmann, I. (2014). Elevated vascular level of ortho -Tyrosine contributes to the impairment of insulin-induced arterial relaxation. Hormone and Metabolic Research, 46(11), 749-752. https://doi.org/10.1055/s-0034-1387701