High levels of xanthine oxidoreductase in rat endothelial, epithelial and connective tissue cells. A relation between localization and function?
The localization of xanthine oxidoreductase activity was investigated in unfixed cryostat sections of various rat tissues by an enzyme histochemical method which specifically demonstrates both the dehydrogenase and oxidase forms of xanthine oxidoreductase. High activity was found in epithelial cells from skin, vagina, uterus, penis, liver, oral and nasal cavities, tongue, esophagus, fore-stomach and small intestine. In addition activity was demonstrated in sinusoidal cells of liver and adrenal cortex, endothelial cells in various organs and connective tissue fibroblasts. Xanthine oxidoreductase produces urate which is a scavenger of oxygen-derived radicals. Because the enzyme is found in epithelial and endothelial cells which are subject to relatively high oxidant stress, it is postulated that in these cells xanthine oxidoreductase is involved in the antioxidant enzyme defense system. In addition, a possible role for the enzyme in proliferation and differentiation processes is discussed.
Laboratory of Cell Biology and Histology, University of Amsterdam, The Netherlands.
A
A
Kooij
K S
KS
Bosch
W M
WM
Frederiks
C J
CJ
Van Noorden
D000302:Adrenal Cortex / Q000201:enzymology; D000818:Animals; D003238:Connective Tissue / Q000201:enzymology*; D004064:Digestive System / Q000201:enzymology; D004727:Endothelium / Q000201:enzymology*; D004848:Epithelium / Q000201:enzymology*; D005260:Female; D008099:Liver / Q000201:enzymology; D008297:Male; D009132:Muscles / Q000201:enzymology; D051381:Rats; D017208:Rats, Wistar; D012137:Respiratory System / Q000201:enzymology; D012867:Skin / Q000201:enzymology; D014527:Uric Acid / Q000378:metabolism; D014566:Urogenital System / Q000201:enzymology; D014968:Xanthine Dehydrogenase / Q000032:analysis*; D014969:Xanthine Oxidase / Q000032:analysis*
D014527:Uric Acid; D014968:Xanthine Dehydrogenase; D014969:Xanthine Oxidase