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Xanthine (IPA: /ˈzænθiːn, ˈzænθaɪn]/), (3,7-dihydro-purine-2,6-dione), is a purine base found in most body tissues and fluids and in other organisms.
Additional recommended knowledge
Xanthine is a product on the pathway of purine degradation.
Xanthine is subsequently converted to uric acid by the action of the xanthine oxidase enzyme.
Clinical significance of xanthine derivatives
Derivatives of xanthine, known collectively as xanthines, are a group of alkaloids commonly used for their effects as mild stimulants and as bronchodilators, notably in treating the symptoms of asthma. In contrast to other, more potent stimulants, they only inhibit the actions of sleepiness-inducing adenosine, making them far less in effective as stimulants than sympathomimetic amines. Due to widespread effects, the therapeutic range of xanthines is narrow, making them merely a second-line asthma treatment. The therapeutic level is 10-20 micrograms/mL blood; signs of toxicity include tremor, nausea, nervousness, and tachycardia/arrhythmia.
Methylated xanthine derivatives include caffeine, paraxanthine, theophylline, and theobromine (found mainly in chocolate). These drugs inhibit phosphodiesterase and antagonise adenosine. Xanthines are also found very rarely as constituents of nucleic acids.
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Xanthine". A list of authors is available in Wikipedia.|