Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.1.1.17 (ornithine decarboxylase)
 6,351 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Relationships between ornithine decarboxylase (ODC) and adenosine diphosphate ribosyl transferase (ADPRT) in human mononuclear leukocytes (HML) were tested by statistical comparisons of their values in a group of 46 people, and by use of inhibitors of ADPRT. 2. ODC was assayed following exposure of HML, for 20 hr, to mitogens [phytohemagglutinin (PHA) and pokeweed mitogen]; ADPRT was measured following exposure of HML to H2O2 (100 microM) for 1 hr (activated ADPRT), and in parallel cultures without H2O2 (constitutive ADPRT). 3. Significant correlations were found between ODC and ADPRT values; the effects of smoking disturbed the correlations. PHA induction of ODC was negatively influenced by age (standardized beta coefficient = -2.95, P = 0.005), while age also influenced ADPRT values negatively in non-smokers (for H2O2 activated ADPRT, standardized beta coefficient = -2.74, P less than 0.008). 4. Inhibitors of ADPRT, nicotinamide, caffeine and benzamide inhibited the induction of ODC by PHA in a concentration-dependent manner, in the range (0.6-10 mM) known to inhibit ADPRT.
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PMID:Mitogenic induction of ornithine decarboxylase in human mononuclear leukocytes: relationships with adenosine diphosphate ribosyltransferase. 213 20

Prolonged treatment with caffeine promotes in rats an increase of liver ornithine carbamyltransferase activity (14-day treatment). In contrast, arginase activity is already reduced in brain and kidney after 10 days, and in the liver much later (17 days). Ornithine transaminase activity was increased in both liver and kidney, while in the brain it was reduced (17 days). Ornithine decarboxylase activity showed only minor modifications in kidney, while it was unchanged in brain. Of the polyamines, only spermidine was significantly modified, being increased in brain, decreased in liver and kidney. Although these results do not explain the mechanism of the modification of brain arginine and ornithine concentration promoted by caffeine, they point to further marked effects, i.e. on OAT activity and on spermidine concentration, which could have a relevant metabolic role.
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PMID:Effect of caffeine on ornithine metabolism in rat brain, liver and kidney. 274 38

I.p. administration of caffeine led to a significant increase in hepatic ornithine decarboxylase activity in rats. The enzyme activity reached approximately 10-fold above the control level 5 h after the injection of caffeine at a dose of 150 mg/kg body weight. The high level of ornithine decarboxylase activity remained for 3 h and then decreased rapidly. The enzyme activity of the kidney, however, was not significantly enhanced by the administration of caffeine. The possible mechanism of the caffeine-mediated hepatic ornithine decarboxylase induction is discussed.
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PMID:Induction of hepatic ornithine decarboxylase by intraperitoneal administration of caffeine in rats. 669 46

Polyamines are found in all cells but their function is not fully understood. We have studied the effect of polyamines on the passage of cells through the cell cycle using a polyamine auxotrophic mutant, CHO-P22, which has no detectable ornithine decarboxylase activity. The ability of these cells to grow without serum allows efficient polyamine depletion. A flow cytometric analysis of DNA content and bromodeoxyuridine labeling showed that without added polyamines the cells accumulated in S-phase, the rate of DNA synthesis was retarded, and the entry into mitosis was blocked. Addition of polyamines to cultures deprived of polyamines induced cells in all phases of the cell cycle to reinitiate cycling. Earlier studies have shown that cells with damaged DNA are blocked from entering into mitosis but caffeine can partly overcome this block and induce premature chromosome condensation. Polyamine-depleted CHO-P22 cells responded to caffeine in the same way as cells with damaged DNA. These results show that polyamine depletion in CHO-P22 cells primarily affects DNA synthesis. The finding that polyamine-starved cells continuously take up bromodeoxyuridine without a corresponding increase in the amount of DNA is compatible with extensive repair of erroneous and/or damaged DNA. Polyamine auxotrophic Chinese hamster ovary (CHO) cells might be useful in studies on the regulation of mitosis in mammalian cells.
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PMID:Flow cytometric analysis of the cell cycle in polyamine-depleted cells. 798 94