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Conversion of xanthine dehydrogenase to oxidase in ischemic rat intestine: a reevaluation.
Conversion of xanthine dehydrogenase to oxidase in ischemic rat intestine: a reevaluation.
- Source :
-
The American journal of physiology [Am J Physiol] 1988 May; Vol. 254 (5 Pt 1), pp. G768-74. - Publication Year :
- 1988
-
Abstract
- Oxygen radicals derived from xanthine oxidase (XO) are important mediators of the cellular injury associated with reperfusion of ischemic intestine, stomach, liver, kidney, and pancreas. XO exists in nonischemic tissue predominantly as xanthine dehydrogenase (XDH) and converts to oxygen radical-producing XO with ischemia. Grinding intestine under liquid nitrogen and placing the powder in phosphate buffer (pH 7.0) containing thiol reductants and protease inhibitors adequately preserved total XDH + XO activity and the percentage in the oxidase form (%XO) for 24 h. Total activity in nonischemic intestine ranged from 374 nmol.min-1.g-1 in duodenum to 138 nmol.min-1.g-1 in ileum, while XO activity was approximately 19% of total activity throughout the entire small intestine. The rate of XDH conversion to XO during normothermic ischemia varied only slightly throughout the intestine, increasing 13% per hour to 34, 46, and 61% XO after 1, 2, and 3 h of ischemia, respectively. Our results contrast with previous reports where XDH conversion to XO occurred within 60 s ischemia but are consistent with physiological and morphological evidence of ischemic injury and provide further support for involvement of XO in intestinal injury associated with ischemia.
- Subjects :
- Animals
Dithiothreitol pharmacology
Free Radicals
Hydrogen-Ion Concentration
Intestines enzymology
Male
Protease Inhibitors pharmacology
Rats
Rats, Inbred Strains
Intestines blood supply
Ischemia enzymology
Ketone Oxidoreductases metabolism
Xanthine Dehydrogenase metabolism
Xanthine Oxidase metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0002-9513
- Volume :
- 254
- Issue :
- 5 Pt 1
- Database :
- MEDLINE
- Journal :
- The American journal of physiology
- Publication Type :
- Academic Journal
- Accession number :
- 3163236
- Full Text :
- https://doi.org/10.1152/ajpgi.1988.254.5.G768