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Effect of methotrexate and 5-fluorodeoxyuridine on ribonucleotide reductase activity in mammalian cells.
- Source :
-
Cancer research [Cancer Res] 1977 Dec; Vol. 37 (12), pp. 4389-94. - Publication Year :
- 1977
-
Abstract
- A number of studies in bacteria have indicated that deoxythymidine 5'-triphosphate may be a repressor or corepressor of ribonucleotide reductase. For determination of whether a similar regulating mechanism exists in mammalian cells, HeLa cells and partially hepatectomized rats were treated with either methotrexate, 5-fluorouracil, or 5-fluorodeoxyuridine in order to block thymidylate synthesis and consequently lower the intracellular pools of deoxythymidine 5'-triphosphate. In HeLa cells there was a significant (360 to 400 percent) increase in reductase activity in both the methotrexate and 5-fluorodeoxyuridine-treated cells. The administration of methotrexate to partially hepatectomized rats resulted in a 2.7-fold enhancement of the hepatectomy-induced increase in reductase activity, and the 5-fluorouracil treatment yielded a 60 percent increment in the increase of ribonucleotide reductase activity after partial hepatectomy. Cycloheximide prevented the increase in reductase activity after the exposure of HeLa cells to methotrexate and 5-fluorodeoxyuridine, indicating that the stimulation of ribonucleotide reductase activity was the result of enhancement of de novo enzyme synthesis rather than of enzyme activation. The data support the thesis that deoxythymidine 5'-triphosphate or a thymidylate metabolite may be involved in the regulation of ribonucleotide reductase levels in mammalian cells.
- Subjects :
- Animals
DNA biosynthesis
Enzyme Induction drug effects
HeLa Cells drug effects
Liver drug effects
Liver Regeneration
Male
Protein Biosynthesis
Rats
Thymine Nucleotides metabolism
Floxuridine pharmacology
HeLa Cells enzymology
Liver enzymology
Methotrexate pharmacology
Ribonucleotide Reductases biosynthesis
Subjects
Details
- Language :
- English
- ISSN :
- 0008-5472
- Volume :
- 37
- Issue :
- 12
- Database :
- MEDLINE
- Journal :
- Cancer research
- Publication Type :
- Academic Journal
- Accession number :
- 144560