Abstract |
Ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase activity (SAMD) were measured in tumour tissue in mice during periods of starvation (24 h) and refeeding. Starvation led to a 60% reduction in tumour ODC activity. Refeeding normalised the activity within 4 h. Restitution in ODC activity, representing de novo enzyme synthesis, preceded DNA resynthesis. SAMD activity continued to fall along the increase in ODC activity during refeeding, while difluoro-methyl- ornithine (DFMO) caused a compensatory increase in SAMD activity as expected. A fall and regain in ODC activity was associated with inhibition and regrowth of the tumour. Starvation-refeeding was not related to any decrease in tumour polyamine concentrations, while systemic DFMO blockade was. Glucose stimulated ODC when refed orally, but not when given systemically. Tumour ODC activity was not decreased in refed mice by anti- insulin, a procedure that antagonised insulin's bioactivity. Exogenous insulin did not stimulate tumour ODC activity. Our results suggest that gastrointestinal metabolism of carbohydrates stimulates the release of a factor, which initiates both ODC activity and DNA synthesis in tumour cells. This factor was not insulin.
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Authors | T Westin, H Zachrisson, S Edström, K Lundholm |
Journal | European journal of cancer (Oxford, England : 1990)
(Eur J Cancer)
Vol. 27
Issue 10
Pg. 1282-8
( 1991)
ISSN: 0959-8049 [Print] England |
PMID | 1835600
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- DNA, Neoplasm
- Insulin
- Insulin Antagonists
- Polyamines
- Ornithine Decarboxylase
- Adenosylmethionine Decarboxylase
- Glucose
- Eflornithine
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Topics |
- Adenosylmethionine Decarboxylase
(metabolism)
- Animals
- DNA, Neoplasm
(biosynthesis)
- Eflornithine
(pharmacology)
- Enzyme Activation
- Food
- Glucose
(pharmacokinetics)
- Insulin
(pharmacology)
- Insulin Antagonists
(pharmacology)
- Mice
- Mice, Inbred C57BL
- Neoplasms, Experimental
(enzymology, pathology)
- Ornithine Decarboxylase
(metabolism)
- Polyamines
(metabolism)
- Starvation
(enzymology)
- Time Factors
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