Nucleolar alterations, caused by 5 fluorouracil (5 FU), were studied in NK/Ly ascites tumor cells by electron microscopic autoradiography. Mice were treated with 250 mg/kg 5 FU i.p. and then injected with 3H uridine. It was found that the nucleoli enlarged; the distribution of 3H uridine between nucleolus and karyoplasm altered, i.e. the number of grains increased in nucleolus and decreased in karyoplasm; there was no marked effect of 5 FU on the concentration of radioactivity of nucleolus and karyoplasm; no labelling appeared at the site of the nucleolar spots which consisted of RNA or RNP containing granules of about 50-80 Å in diameter. It is suggested that the incorporation of 5 FU into nucleolar RNA gives rise to the formation of abnormal precursor ribosomal RNA which congregates into spots. The fact that labelling was seen outside the spots shows that in spite of the inhibited metabolism of certain RNA the synthesis of others is further continued in the spotted nucleoli.
|Number of pages||6|
|Publication status||Published - Dec 1 1973|
ASJC Scopus subject areas
- Cancer Research