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

Research output: Contribution to journalArticlepeer-review

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
StatePublished - Jun 2006

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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