title: Effect of aza-substituted nucleotides on the starve-refeed response of rats.
abstract: Rat liver glucose 6-phosphate dehydrogenase (G6PD) and malic enzyme (ME) activities were increased by starvation-refeeding to levels above those found in rats fed ad libitum. The increases in enzyme activities above ad libitum-fed levels were prevented by 8-azaguanine and 6-azauridine, but not by 2-azauridine. Blood insulin levels were not affected at the time studied. Two aza analogs, 8-azaadenine and 5-azacytidine, proved to be too toxic in this type of studies. Since 8-azahypoxanthine, 8-azaxanthine and 5-azauracil were neither effective in preventing the enzyme overshoot, nor toxic to the animals, it was concluded that the toxiciyty to the animals of 8-azaadenine and 5-azacytidine is due to the compounds themselves rather than to the breakdown products.
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001372:Aza Compounds; D001374:Azacitidine / Q000494:pharmacology; D001375:Azaguanine / Q000494:pharmacology; D001380:Azauridine / Q000494:pharmacology; D005247:Feeding Behavior / Q000187:drug effects*; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D007042:Hypoxanthines / Q000494:pharmacology; D008099:Liver / Q000201:enzymology; D008291:Malate Dehydrogenase / Q000378:metabolism; D008297:Male; D009711:Nucleotides / Q000494:pharmacology*; D051381:Rats; D013217:Starvation; D014498:Uracil / Q000031:analogs & derivatives / Q000494:pharmacology; D014970:Xanthines / Q000494:pharmacology
chemical_list: D001372:Aza Compounds; D007042:Hypoxanthines; D009711:Nucleotides; D014970:Xanthines; D014498:Uracil; D001380:Azauridine; D008291:Malate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase; D000225:Adenine; D001374:Azacitidine; D001375:Azaguanine