Relationship between nucleolar microspherule formation by urethan and inhibition of RNA and protein synthesis
Lombardi, L.
Cancer Research 36(7 Pt 1): 2210-2215
1976
ISSN/ISBN: 0008-5472 PMID: 1277126 Document Number: 99724
Liver tissues of suckling C3Hf mice treated with urethan, a carcinogen and inhibitor of RNA synthesis, and cycloheximide, an inhibitor of protein synthesis, were studied by EM and light microscope radioautography. At 4 and 12 h after treatment with a single dose of urethan (1 mg/g body weight), [3H]uridine incorporation in hepatocyte nuclei was 38 and 9% lower than in controls and became 32% higher at 24 h. Nucleolar microspherules were found 1.5 and 4 h after treatment, increased considerably in number at 10 and 12 h and decreased at 24 h. These results suggest an inverse relationship between RNA synthesis and formation of microspherules. Cycloheximide alone (3 mg/kg body weight) produced microspherules, whereas in combination with a dose of 1 or 2 mg of urethan/g body weight it partially prevented or potentiated, respectively, microspherule production.