Modulation of renal xanthine oxidoreductase in aging: Gene expression and Reactive Oxygen Species generation

Hae Young Chung, Sang Ho Song, Hyon Jeen Kim, Yuji Ikeno, Byung Pal Yu

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Xanthine oxidoreductase (XD: xanthine dehydrogenase + xanthine oxidase) is a complex enzyme that catalyzes oxidation of hypoxathine to xanthine, subsequently producing uric acid. The enzyme complex exists in separate but interconvertible forms, xanthine dehydrogenase (XDH) and xanthine oxidase (XOD). XOD is one of the major cellular sources of superoxide production and is well known as a causative factor in ischemia/reperfusion damage. At present, almost no information on the conversion status is available with respect to aging. In the present study, we investigated the effect of age on the XOD/XDH status and gene expression in the kidney. In addition, we assessed XOD-induced reactive oxygen species (ROS) using the dichlorofluoroscein (DCF) method. Our results show that XD activity gradually up to 18 months of age and then a slight decrease at 24 months of age. XDH activity showed increases up to 18 months of age, then decreased at 24 months of age. The conversion of XDH to XOD, assessed by changes in the ratios of XOD/(XOD+XDH), showed an age-related increase, which peaked at 24 months. Levels of XD protein and its mRNA paralleled to overall XD activity. ROS generation has tendency to increase with age. Our results suggest that the increased conversion of XDH to XOD observed with age may be an important contributing factor to the increased renal oxidative stress during aging.

Original languageEnglish (US)
Pages (from-to)19-23
Number of pages5
JournalJournal of Nutrition, Health and Aging
Issue number1
StatePublished - Dec 1 1999


  • Aging
  • Gene expression
  • Kidney
  • Reactive oxygen species
  • Xanthine dehydrogenase
  • Xanthine oxidase

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics
  • Geriatrics and Gerontology

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