Metabolism of uridine and determination of liver ribonucleic acid synthesis in developing and adult mice.
The metabolism of [5-3H]uridine and the incorporation of the precursor into liver RNA was studied in developing (13-day-old) and adult (45-day-old) mice. Different time-courses of labelling and increased amounts of labelled catabolic products of uridine were found in liver and blood of developing mice compared with adult animals. This is suggested to be a consequence of enlarged metabolite pools resulting from a lower total amount of uracil-degrading enzymes in the developing mice. The labelling of the uracil nucleotides was decreased in the developing liver. However, in spite of a lower specific radioactivity of UTP, the RNA-specific radioactivity of developing liver was increased compared with adult liver. Also the labelling of liver RNA with [6-14C]orotic acid was found to be increased in developing mice, thus indicating a higher rate of RNA synthesis in these animals. A more pronounced difference in liver RNA labelling between the developing and the adult mice obtained with the use of [14C]orotic acid than with [3H]uridine may suggest that the de novo pathway, relative to the salvage pathways, is more important in developing than in adult liver.
Engelbrecht
C
C
Yngner
T
T
D000375:Aging; D000409:Alanine / Q000378:metabolism; D000818:Animals; D008099:Liver / Q000254:growth & development* / Q000378:metabolism; D008297:Male; D051379:Mice; D009963:Orotic Acid / Q000378:metabolism; D012313:RNA / Q000096:biosynthesis* / Q000378:metabolism*; D014316:Tritium; D014498:Uracil / Q000031:analogs & derivatives / Q000378:metabolism; D014529:Uridine / Q000097:blood / Q000378:metabolism*; D014542:Uridine Monophosphate / Q000378:metabolism; D014544:Uridine Triphosphate / Q000378:metabolism; D015091:beta-Alanine / Q000031:analogs & derivatives / Q000378:metabolism
C007419:dihydrouracil; D014316:Tritium; D015091:beta-Alanine; C035122:N-carbamoyl-beta-alanine; D014498:Uracil; D009963:Orotic Acid; D012313:RNA; D014542:Uridine Monophosphate; D000409:Alanine; D014544:Uridine Triphosphate; D014529:Uridine