Xanthine oxidase: evidence against a causative role in renal reperfusion injury
Joannidis, M.; Gstraunthaler, G.; Pfaller, W.
American Journal of Physiology 258(2 Pt 2): F232-F236
1990
ISSN/ISBN: 0002-9513 PMID: 2309886 Document Number: 365537
The conversion rates of xanthine dehydrogenase (XDH) to xanthine oxidase (XO) were compared with the time course of in vivo lipid peroxidation (LPO) in an ischemia-reperfusion model of acute renal failure in the rat. LPO, measured as the renal release of malondialdehyde (MDA), was found to be markedly elevated only during the first 5 min of blood reflow following a 45-min interval of ischemia (arteriovenous MDA difference -277.3 .+-. 53.5 vs. 3.7 .+-. 5.7 nmol/l in controls, n = 14). After 30 min of reperfusion, arteriovenous MDA differences nearly reached control values (9.7 .+-. 31.8 nmol/l, n = 7). In contrast to enhanced LPO, no significant conversion of XDH to XO was found (XO activity in controls: 23 .+-. 1% of XO plus XDH activity vs. 26 .+-. 3% after 45 min of ischemia, n = 7). Therefore XO-derived superoxide anion radicals cannot be considered causative for LPO in the reperfusion interval of experimental ischemic acute renal failure.