scholarly journals Ornithine decarboxylase activity and the onset of deoxyribonucleic acid synthesis in regenerating liver

1978 ◽  
Vol 170 (1) ◽  
pp. 123-127 ◽  
Author(s):  
J A McGowan ◽  
N Fausto
Keyword(s):  
Dna Synthesis ◽  
Ornithine Decarboxylase ◽  
Time Course ◽  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Decarboxylase Activity ◽  
Ornithine Decarboxylase Activity ◽  
Low Protein ◽  
Deoxyribonucleic Acid Synthesis ◽  
Second Peak

Compared with normally fed animals, rats fed on a low-protein diet for 3 days exhibit a considerable delay in DNA synthesis after partial hepatectomy. In the regenerating livers of these animals (a) the timing of the first peak of ornithine decarboxylase activity is not altered and (b) the second peak of enzyme activity is delayed by a few hours, but polyamine concentrations are similar to those of normally fed rats. The results suggest that regardless of the possible effect of polyamines on DNA synthesis, the time course of ornithine decarboxylase activity appears to be independent of the onset of DNA replication in regenerating livers.

scholarly journals Ornithine decarboxylase and polyamines in liver and kidneys of rats on cyclical regimen of protein-free and protein-containing diets. Relationship to deoxyribonucleic acid synthesis in liver

1977 ◽  
Vol 168 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Donald C. Farwell ◽  
Jose B. Miguez ◽  
Edward J. Herbst
Keyword(s):  
Dna Synthesis ◽  
Ornithine Decarboxylase ◽  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Multiple Injections ◽  
Deoxyribonucleic Acid Synthesis ◽  
Cyclical Regimen ◽  
Protein Free Diet ◽  
Fold Stimulation ◽  
Stimulation Of

1. The activity of ornithine decarboxylase in the liver and kidneys of rats maintained on a cyclical regimen of protein-free and protein-containing diets was investigated. There was a daily activation of the enzyme in response to the feeding of protein after 3 days feeding of protein-free diet. 2. The activation of ornithine decarboxylase in the liver and kidneys of rats re-fed on protein was demonstrable throughout 16 cycles of alternating 3-day periods of protein-free and protein-containing diets. The magnitude of the activation in the kidneys diminished from 20-fold stimulation in the first cycle to 5-fold stimulation (compared with animals fed with protein-free diet) in the later cycles of protein re-feeding. The activation of the enzyme in liver was decreased from 20-fold stimulation in the first cycle to approx. 10-fold stimulation in later cycles. 3. The concentration of spermidine was increased by approx. 50% in the liver of animals during cycling from protein-free to protein-containing diets. Spermine was unchanged, and putrescine was maintained at a low concentration approx. one-fifth to one-tenth that of spermidine after protein re-feeding. 4. The incorporation of [3H]thymidine into liver DNA was increased 10-fold in animals re-fed with protein compared with animals receiving protein-free diets. 5. The activation of ornithine decarboxylase by re-feeding of protein was inhibited 90% by the injection of propane-1,3-diamine during re-feeding. The stimulation of DNA synthesis was inhibited 60% by multiple injections of propane-1,3-diamine during the re-feeding of protein.

Ornithine decarboxylase activity and DNA synthesis in Morris hepatomas 51123-C and 7800

Life Sciences ◽  
1976 ◽  
Vol 18 (1) ◽  
pp. 39-48 ◽  
Author(s):  
Michael W. Pariza ◽  
Susumu Yanagi ◽  
James A. Gurr ◽  
Donald E. Bushnell ◽  
Harold P. Morris ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Ornithine Decarboxylase ◽  
Decarboxylase Activity ◽  
Ornithine Decarboxylase Activity

Effects of Acute and Subchronic Exposure of Topically Applied Fullerene Extracts on the Mouse Skin

1993 ◽  
Vol 9 (4) ◽  
pp. 623-630 ◽  
Author(s):  
Mark A. Nelson ◽  
Frederick E. Domann ◽  
G. Tim Bowden ◽  
Stephen B. Hooser ◽  
Quintus Fernando ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Ornithine Decarboxylase ◽  
Mouse Skin ◽  
Tumor Formation ◽  
Skin Tumor ◽  
Toxic Effects ◽  
Exposure Level ◽  
Decarboxylase Activity ◽  
Ornithine Decarboxylase Activity ◽  
Acute Toxic

The recent discovery that fullerenes (C60) can be produced in macroscopic quantities has sparked much interest in the chemistry of this unusual molecule. Concerns have also arose about the potential carcinogenic effects of this molecule. We have addressed the potential acute and subchronic toxic effects of fullerenes applied in benzene on the mouse skin. The acute toxic effects measured in this study included epidermal DNA synthesis and the induction of ornithine decarboxylase activity in the epidermis. At the topical dose of fullerenes used in these studies (i.e., 200 ug), we found no effect on either DNA synthesis or ornithine decarboxylase activity over a 72 hour time course after treatment. The subchronic effects of the fullerenes as a mouse skin tumor promoter was assessed by repeatedly applying the chemical to the skin after initiation with the polycyclic aromatic hydrocarbon, 7,12-dimethlybenz-anthracene (DMBA). Repeated administration of the fullerenes for up to 24 weeks post-initiation did not result in either benign or malignant skin tumor formation, whereas promotion with the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA) resulted in the formation of benign skin tumors. Our data indicate that fullerenes applied in benzene at a likely industrial exposure level do not cause acute toxic effects on the mouse skin epidermis.

scholarly journals Effect of drugs on deoxyribonucleic acid synthesis in isolated mammalian cell nuclei. Comparison with partially purified deoxyribonucleic acid polymerases

1979 ◽  
Vol 178 (3) ◽  
pp. 621-626 ◽  
Author(s):  
J F Burke ◽  
P M Duff ◽  
C K Pearson
Keyword(s):  
Dna Synthesis ◽  
Dna Polymerase ◽  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Cell Nuclei ◽  
Isolated Nuclei ◽  
Dna Polymerase Alpha ◽  
Polymerase Beta ◽  
Deoxyribonucleic Acid Synthesis

In order to ascertain the identity of the DNA-dependent DNA polymerase responsible for the observed DNA synthesis in nuclei isolated from baby-hamster kidney (BHK-21/C13) cells a comparative study was carried out on the effects of some drugs, reported to influence DNA synthesis, on DNA synthesis catalysed by these nuclei and by partially purified DNA polymerase-alpha and -beta. In all cases DNA synthesis by isolated nuclei and polymerase-alpha was inhibited to similar extents by N-ethylmaleimide, p-hydroxymercuribenzoate, novobiocin, heparin and phosphonoacetic acid; polymerase-beta was much less affected by these compounds. Ethidium bromide inhibited all DNA synthesis to similar extents, although at low concentrations (about 2 microgram/ml) synthesis in isolated nuclei was stimulated. The results are discussed in relation to the proposal that DNA polymerase-alpha catalyses the covalent extension of Okazaki fragments that these nuclei carry out in vitro.

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