scholarly journals Inhibition of polyamine accumulation and deoxyribonucleic acid synthesis in regenerating rat liver

1976 ◽  
Vol 158 (2) ◽  
pp. 485-488 ◽  
Author(s):  
H Pösö ◽  
J Jänne
Keyword(s):  
Partial Hepatectomy ◽  
Ornithine Decarboxylase ◽  
Rat Liver ◽  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Liver Protein ◽  
Polyamine Synthesis ◽  
Total Liver ◽  
Regenerating Rat Liver ◽  
Deoxyribonucleic Acid Synthesis

Repeated injections of 1,3-diaminopropane into rats after partial hepatectomy caused a repression-type inhibiton of liver ornithine decarboxylase (EC 4.1.1.17) and totally prevented the marked increases in liver putrescine and spermidine concentrations that normally occur in response to partial hepatectomy. The inhibition of polyamine synthesis by diaminopropane was accompanied by a profound decrease (about 80%) in the synthesis of DNA in the regenerating rat liver without any changes in the synthesis of RNA and total liver protein.

scholarly journals Regenerating Rat Liver: Correlations Between Estrogen Receptor Localization and Deoxyribonucleic Acid Synthesis

1984 ◽  
Vol 86 (3) ◽  
pp. 552-557 ◽  
Author(s):  
Antonio Francavilla ◽  
Alfredo Di Leo ◽  
Patricia K. Eagon ◽  
Shi-Quin Wu ◽  
Peter Ove ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Rat Liver ◽  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Receptor Localization ◽  
Regenerating Rat Liver ◽  
Deoxyribonucleic Acid Synthesis

scholarly journals Effect of inhibition of polyamine synthesis on the content of decarboxylated S-adenosylmethionine

1982 ◽  
Vol 202 (2) ◽  
pp. 519-526 ◽  
Author(s):  
Anthony E. Pegg ◽  
Hannu Pösö ◽  
Kay Shuttleworth ◽  
Richard A. Bennett
Keyword(s):  
Partial Hepatectomy ◽  
Ornithine Decarboxylase ◽  
Rat Liver ◽  
Adenine Nucleotides ◽  
3T3 Cells ◽  
Direct Inhibition ◽  
Polyamine Synthesis ◽  
Mouse Fibroblasts ◽  
Regenerating Rat Liver ◽  
Specific Inhibitors

1. The content of decarboxylated S-adenosylmethionine (AdoMet) in transformed mouse fibroblasts (SV-3T3 cells) was increased 500-fold to about 0.4fmol/cell when ornithine decarboxylase was inhibited by α-difluoromethylornithine. This increase was due to the absence of putrescine and spermidine, which serve as substrates for aminopropyltransferases with decarboxylated AdoMet as an aminopropyl donor, and to the enhanced activity of AdoMet decarboxylase brought about by depletion of spermidine. The increase in decarboxylated AdoMet content was abolished by addition of putrescine, but not by 1,3-diaminopropane. 2. 5′-Methylthiotubercidin also increased decarboxylated AdoMet content, presumably by direct inhibition of aminopropyl-transferase activities, but the increase in its content and the decline in spermidine content were much less than those produced by α-difluoromethylornithine. 3. Decarboxylated AdoMet content of regenerating rat liver was measured in rats treated with inhibitors of ornithine decarboxylase. The content was increased by 60% 32h after partial hepatectomy in control rats, by 90% when α-difluoromethylornithine was given to the partially hepatectomized rats, and by 330% when 1,3-diaminopropane was used to inhibit putrescine and spermidine synthesis. After 48h of exposure to 1,3-diaminopropane, which completely prevented the increase in spermidine after partial hepatectomy, there was a 5-fold rise in hepatic decarboxylated AdoMet concentration. These increases were prevented by treatment with putrescine or with methylglyoxal bis(guanylhydrazone), an inhibitor of AdoMet decarboxylase. 4. These results show that changes in AdoMet metabolism result from the administration of specific inhibitors of polyamine synthesis. The possible consequences of the accumulation of decarboxylated AdoMet, which could, for example, interfere with normal cellular methylation or lead to depletion of cellular adenine nucleotides, should be considered in the interpretation of results obtained with such inhibitors.

DEOXYCYTIDYLATE DEAMINASE LEVELS IN REGENERATING RAT LIVER

1961 ◽  
Vol 39 (6) ◽  
pp. 1043-1054 ◽  
Author(s):  
D. K. Myers ◽  
C. Anne Hemphill ◽  
Constance M. Townsend
Keyword(s):  
Dna Synthesis ◽  
Liver Regeneration ◽  
Partial Hepatectomy ◽  
Rat Liver ◽  
Deoxyribonucleic Acid ◽  
Regenerating Liver ◽  
Regenerating Rat Liver ◽  
High Level ◽  
Early Regeneration

Deoxycytidylate deaminase activity and net synthesis of deoxyribonucleic acid (DNA) in vivo were found to increase at approximately the same time during the early stages of liver regeneration. However, deaminase activity in the regenerating liver remained at a high level for 1 day after DNA synthesis had slowed down again during the later stages of regeneration. The increase in deaminase activity was restricted as a result of exposure to 600 r X radiation during early regeneration, but this effect only became evident 11–16 hours after the irradiation. Irradiation on the second day after partial hepatectomy, when deaminase levels in control regenerating livers were relatively constant, failed to affect the deaminase activity immediately but did produce a 40–50% decrease in activity 11–16 hours later. Other antimitotic agents, e.g., colchicine, had little effect on deaminase activity.

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.

Sign in / Sign up

Export Citation Format

Share Document