Metabolic alterations of liver regeneration. XI. Modulation of the uptake of orotic acid into ribonucleic acids in regenerating rat liver

1973 ◽  
Vol 38 (12) ◽  
pp. 3944-3951 ◽  
Author(s):  
A. Čihák ◽  
J. Veselý ◽  
F. Šorm
Keyword(s):  
Liver Regeneration ◽  
Rat Liver ◽  
Orotic Acid ◽  
Ribonucleic Acids ◽  
Metabolic Alterations ◽  
Regenerating Rat Liver

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 Increased synthesis of low-molecular-weight nuclear ribonucleic acids of rat liver after γ irradiation and hepatectomy

1975 ◽  
Vol 146 (2) ◽  
pp. 357-360 ◽  
Author(s):  
A Fónagy ◽  
E J Hidvégi
Keyword(s):  
Molecular Weight ◽  
Partial Hepatectomy ◽  
Rat Liver ◽  
Orotic Acid ◽  
Low Molecular Weight ◽  
Polyacrylamide Gels ◽  
Γ Irradiation ◽  
Ribonucleic Acids

Incorporation of [3H]orotic acid into low-molecular-weight nRNA of rat liver, fractionated on polyacrylamide gels, increased 6-12h after partial hepatectomy and 6h after γ-irridation at 2000 R. The incorporation of orotic acid was particularly increased into the 4.5S, 5S and approx. 10S nRNA fractions. If the irradiation was given after 6h of regeneration and RNA was isolated from the nucleus 12h after hepatectomy then the incorporation of orotic acid into these low-molecular-weight nRNA components was greater than after hepatectomy or irradiation alone.

scholarly journals Observations on iron uptake, iron metabolism, cytochrome c content, cytochrome a content and cytochrome c-oxidase activity in regenerating rat liver

1965 ◽  
Vol 97 (2) ◽  
pp. 532-539 ◽  
Author(s):  
ARL Gear
Keyword(s):  
Cytochrome C ◽  
Liver Regeneration ◽  
Cytochrome C Oxidase ◽  
Density Gradient ◽  
Rat Liver ◽  
Oxidase Activity ◽  
Specific Content ◽  
Cytochrome C Reductase ◽  
Regenerating Rat Liver ◽  
Mitochondrial Fractions

1. Differential and density-gradient centrifugation were used to fractionate mitochondria and fluffy layer from normal and regenerating rat liver. The iron, cytochrome a and cytochrome c contents and cytochrome c-oxidase activity were studied as well as the uptake of (59)Fe into protein and cytochrome c. 2. A certain degree of heterogeneity was evident between the heavy-mitochondrial and light-mitochondrial fractions, and in their behaviour during liver regeneration. 3. The specific content of light-mitochondrial iron and cytochrome a was 1.3-1.4 times that of heavy mitochondria. Changes in cytochrome c-oxidase activity closely followed those of cytochrome a content during liver regeneration, but not for light mitochondria after 10 days. 4. Radioactive iron ((59)Fe) was most actively taken up by well-washed light mitochondria during early liver regeneration. After 22 days fluffy layer became preferentially labelled. This substantiates the view that fluffy layer partially represents broken-down mitochondria. 5. During early regeneration, light-mitochondrial fractions separated along a density gradient were about 3 times as radioactive, and showed distinct heterogeneity of (59)Fe-labelling, in contrast with near homogeneity for heavy mitochondria. 6. Immediately after partial hepatectomy fractions corresponding to density 1.155 were 5-10 times as radioactive as particles of greater density. The radioactivity decreased sharply after 6 days. 7. These particles of low density possessed higher NADH-cytochrome c-reductase (1.5-5-fold) and succinate-dehydrogenase (1.1-2-fold) activities than typical mitochondrial fractions. Their succinate-cytochrome c-reductase and cytochrome c-oxidase activities were slightly lower. 8. The results are discussed in relation to mitochondrial morphogenesis, and a possible route from submitochondrial particles is suggested.

RIBONUCLEASE ACTIVITY IN REGENERATING RAT LIVER

1967 ◽  
Vol 45 (7) ◽  
pp. 1021-1026 ◽  
Author(s):  
D. J. S. Arora ◽  
G. de Lamirande
Keyword(s):  
Enzymatic Activity ◽  
Liver Regeneration ◽  
Partial Hepatectomy ◽  
Rat Liver ◽  
Ribonucleic Acid ◽  
Ribonuclease Activity ◽  
Regenerating Liver ◽  
Early Stages ◽  
Regenerating Rat Liver ◽  
Ribonucleoprotein Particles

Ribonucleoprotein particles were isolated from sham-hepatectomized and partially hepatectomized animals. The levels of ribonucleic acid and of proteins, as well as the ribosomal ribonuclease activity, have been studied in regenerating liver at periods of 4, 8, 16, 36, and 72 hours after partial hepatectomy. The results showed that the amount of ribosomes in regenerating rat liver was not affected as compared with the level observed in sham-operated rats. However, a decrease of ribonuclease activity was noticed in the early stages of liver regeneration. The ribonuclease activity was practically negligible at 16 and 36 hours. Less than 50% of the enzymatic activity was regained at the 72-hour period after partial hepatectomy.Results show that the ribosomes from regenerating liver are more stable and the stabilizing factor seems to be the absence of ribonuclease.

STUDIES ON LIVER REGENERATION: I.131IODODEOXYURIDINE AS A PRECURSOR of DNA IN NORMAL and REGENERATING RAT LIVER

1971 ◽  
Vol 4 (6) ◽  
pp. 519-527
Author(s):  
K. Bürki ◽  
J. C. SCHAER ◽  
A. Grieder ◽  
R. Schindler ◽  
H. Cottier
Keyword(s):  
Liver Regeneration ◽  
Rat Liver ◽  
Regenerating Rat Liver

scholarly journals Regulated transcription of c-Ki-ras and c-myc during compensatory growth of rat liver.

1984 ◽  
Vol 4 (8) ◽  
pp. 1493-1498 ◽  
Author(s):  
M Goyette ◽  
C J Petropoulos ◽  
P R Shank ◽  
N Fausto
Keyword(s):  
Dna Synthesis ◽  
Liver Regeneration ◽  
Partial Hepatectomy ◽  
Rat Liver ◽  
Compensatory Growth ◽  
Chemical Injury ◽  
Regenerating Rat Liver ◽  
Regenerative Growth ◽  
Cellular Oncogenes

We examined the transcription of six cellular oncogenes during the process of compensatory growth in rat liver after partial hepatectomy. We have previously reported that transcripts of c-rasH are elevated during regenerative growth of the liver. We now report that transcripts of c-rasK and c-myc genes are significantly elevated after partial hepatectomy, whereas transcripts of c-abl and c-src are essentially unchanged and transcripts of c-mos are undetectable in either normal or regenerating rat liver. In liver regeneration after partial hepatectomy or chemical injury, changes in c-myc transcripts occur before DNA synthesis. The elevation of c-myc and c-ras transcripts is sequential in that highest levels of c-myc transcripts were detected 12 to 18 h after partial hepatectomy, whereas the levels of c-rasH and c-rasK were maximal by 36 to 48 h. Transcripts of all three activated oncogenes returned to their basal levels by 96 h.

scholarly journals Quantitative alterations in the nucleolar and nucleoplasmic ribosomal ribonucleic acids in regenerating rat liver

1982 ◽  
Vol 204 (1) ◽  
pp. 179-183 ◽  
Author(s):  
Mariana D. Dabeva ◽  
Kalin P. Dudov
Keyword(s):  
Quantitative Analysis ◽  
Rat Liver ◽  
Rrna Processing ◽  
Regenerating Liver ◽  
Ribonucleic Acids ◽  
Regenerating Rat Liver ◽  
Rrna Species ◽  
The Absolute ◽  
Pool Sizes

A quantitative analysis of the nuclear pre-rRNA (precursor to rRNA) and rRNA in normal and 12h-regenerating rat liver was carried out, and the absolute amounts of the identified pre-rRNA and rRNA species in the nucleolus and nucleoplasm were determined. Characteristic changes in the pre-rRNA and rRNA pool sizes in regenerating liver are found which reveal alternations in both pre-rRNA processing and nucleocytoplasmic transition of ribosomes.

Regulated transcription of c-Ki-ras and c-myc during compensatory growth of rat liver

1984 ◽  
Vol 4 (8) ◽  
pp. 1493-1498
Author(s):  
M Goyette ◽  
C J Petropoulos ◽  
P R Shank ◽  
N Fausto
Keyword(s):  
Dna Synthesis ◽  
Liver Regeneration ◽  
Partial Hepatectomy ◽  
Rat Liver ◽  
Compensatory Growth ◽  
Chemical Injury ◽  
Regenerating Rat Liver ◽  
Regenerative Growth ◽  
Cellular Oncogenes

We examined the transcription of six cellular oncogenes during the process of compensatory growth in rat liver after partial hepatectomy. We have previously reported that transcripts of c-rasH are elevated during regenerative growth of the liver. We now report that transcripts of c-rasK and c-myc genes are significantly elevated after partial hepatectomy, whereas transcripts of c-abl and c-src are essentially unchanged and transcripts of c-mos are undetectable in either normal or regenerating rat liver. In liver regeneration after partial hepatectomy or chemical injury, changes in c-myc transcripts occur before DNA synthesis. The elevation of c-myc and c-ras transcripts is sequential in that highest levels of c-myc transcripts were detected 12 to 18 h after partial hepatectomy, whereas the levels of c-rasH and c-rasK were maximal by 36 to 48 h. Transcripts of all three activated oncogenes returned to their basal levels by 96 h.

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