Title: Correlations of tissue oxypurine levels with xanthine dehydrogenase changes in the chick
Abstract: A method was developed for determinating uric acid and hypoxanthine plus xanthine pools in chicken tissues and was applied to the examination of pool fluctuations in association with changes in xanthine dehydrogenase activity. P. C. Lee and J. R. Fisher (Arch. Biochem. Biophys., 148 (1972) 277) suggested that liver xanthine dehydrogenase regulation involves either product repression or substrate (or substrate precursor) induction. Results presented here favor substrate induction over product repression as the regulating mechanism. Correlations between changes in xanthine dehydrogenase and tissue uric acid levels clearly reveal the importance of the enzyme in regulating pool sizes of this metabolite. A lack of direct correlation between hypoxanthine plus xanthine pools and xanthine dehydrogenase changes indicates that xanthine dehydrogenase does not play a major role in the control of total purine flux. Marked differences were observed between the effects of allopurinol on chicken oxypurine levels and the reported effects of this inhibitor on human oxypurine levels. These differences are attributed to variations between mammalian and avian systems with respect to purine flux control and kidney function. Results from developmental and allopurinol injection experiments suggest that, with the exception of the kidney, chicken tissues having high xanthine dehydrogenase activity derive oxypurine pools endogenously without obtaining significant levels of these metabolites from the circulation.
Publication Year: 1972
Publication Date: 1972-05-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
Access and Citation
Cited By Count: 10
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