The Effect of 5-Fluoroorotic Acid on the Early Labelling of Nucleotides and RNA in Whole Liver and of RNA in Subnuclear Fractions in Rats Given 3H-Orotic Acid
Male white rats were given either orotic acid or 5-fluoroorotic acid 60 min, and 3H-orotic acid 3 1/2 min before sacrifice. Liver nucleotides were analyzed by isotachophoresis. The (F)UTP pool increased to the same extent in both groups and showed the same specific labelling. The RNA synthesis, as measured by nmol of UTP entering RNA-UMP/g wet liver tissue was significantly lower in f.luoroorotic acid treated rats.In the nucleolar fraction there was an increase in the RNA/DNA ratio, a decrease in the specific RNA labelling and an essentially unaltered specific labelling of RNA/ pg/DNA. The effect on the specific labelling of RNA/pg DNA was the same in the nucleolar fraction and the nucleolar-free pellet, suggesting that the transcription of RNA in these two fractions proceeded in a similar way. There was a slight increase in the specific RNA labelling of the supernatant subnuclear fraction, containing low-molecular weight RNA. Incorporation into UDP-hexoses and UDP-N-acetylhexoseamine was unchanged.
KeywordsRibonucleic Acid Specific Labelling Orotic Acid Early Labelling Liver Cytoplasm
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- 3.U. Stenram and R. Willén, The effect of 5-fluorouracil on ultra-structure and RNA labelling in the liver of rats following partial hepatectomy, Chem.-Biol. Interactions 2: 79–88 (1970).Google Scholar
- 5.A. A. Hadjiolov and K. V. Hadjiolova, The effect of 5-fluoropyrimidines on the processing of ribonucleic acids in liver, FEES Symposium 57: 77–84 (1979).Google Scholar
- 6.D. S. Wilkinson, A. Cihak and H. C. Pitot, Inhibition of ribosomal ribonucleic acid maturation in rat liver by 5-fluoroorotic acid resulting in the selective labeling of cytoplasmic messenger ribonucleic acid, J. Biol. Chem. 216: 6418–6427 (1971).Google Scholar
- 8.R. I. Glazer and K. D. Hartman, The effect of 5-fluorouracil on the synthesis and methylation of low molecular weight nuclear RNA in L1210 cells, Molec. Pharmacol. 17: 245–249 (1980).Google Scholar
- 9.G. Eriksson, A method for measuring nucleotides in the liver of rat with isotachophoresis, Analyt. Biochem. 109: 239–246 (1980).Google Scholar