Impact of angiotensin-converting enzyme inhibition on renal cortical nitrotyrosine content during increased extracellular glucose concentration

Naohito Ishii, Hideki Ikenaga, Pamela K Carmines, Nobukazu Takada, Toshio Okazaki, Tatsuo Nagai, Tadakazu Maeda, Yoshikazu Aoki, Takao Saruta, Masato Katagiri

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2 Scopus citations

Abstract

Objectives: Experiments evaluated the hypothesis that angiotensin-converting enzyme (ACE) inhibition suppresses hyperglycemia-induced nitrotyrosine (NT) production in the renal cortex. Design and methods: Rats were untreated (UNTR, n = 6) or received the ACE inhibitor enalapril (20 mg/kg/day; ENAL, n = 6) for 2 weeks. Renal cortical slices were incubated for 90 min in media containing 5 (normal) or 20 mmol/L (high) glucose. Superoxide anion (O2·-) and nitrate + nitrite (NOX) levels were measured in the media. Superoxide dismutase (SOD) activity and NT content were measured in the tissue homogenate. Results: In the UNTR group, high glucose increased O2·- and NOX production by the renal cortex (P < 0.05 vs. normal glucose). Likewise, NT content and SOD activity of the renal cortex augmented (P < 0.05 vs. normal glucose). In the ENAL group, O2·- production and NT content were glucose-insensitive, but high glucose exerted an exaggerated impact on NOX production and SOD activity (P < 0.01 vs. UNTR in high glucose). Conclusion: Accelerated NT content in the renal cortex during high-glucose conditions was prevented by ACE inhibitor treatment. It was suggested that, apart from its anti-hypertensive effect, the mechanism of suppressed NT degradation in the renal cortex by the ACE inhibitor enhances both O2·- degradation per se and antioxidative effects including SOD activation.

Original languageEnglish (US)
Pages (from-to)633-639
Number of pages7
JournalClinical Biochemistry
Volume39
Issue number6
DOIs
Publication statusPublished - Jun 1 2006

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Keywords

  • Angiotensin-converting enzyme inhibition
  • Diabetes mellitus
  • Nitric oxide
  • Peroxynitrite
  • Protein tyrosine nitration
  • Superoxide anion
  • Superoxide dismutase

ASJC Scopus subject areas

  • Clinical Biochemistry

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