Suppression and acceleration of DNA synthesis in megakaryocytes after partial hepatectomy

1984 ◽  
Vol 46 (1) ◽  
pp. 127-133 ◽  
Author(s):  
T. Hattori ◽  
B. Helpap ◽  
P. Gedigk
Keyword(s):  
Dna Synthesis ◽  
Partial Hepatectomy

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.

Effects of pHGF on renal cellular DNA synthesis after partial hepatectomy in rats

2000 ◽  
Vol 20 (1) ◽  
pp. 55-56
Author(s):  
Liao Jiazhi ◽  
Tang Wangxian ◽  
Wang Junping ◽  
Zhang Wenying
Keyword(s):  
Dna Synthesis ◽  
Partial Hepatectomy ◽  
Cellular Dna

Effect of thyroparathyroidectomy on the activities of thymidylate synthetase and thymidine kinase during liver regeneration after partial hepatectomy

1987 ◽  
Vol 72 (4) ◽  
pp. 455-461 ◽  
Author(s):  
Rieko Nakata ◽  
Ikuyo Tsukamoto ◽  
Masamitsu Miyoshi ◽  
Shosuke Kojo
Keyword(s):  
Dna Synthesis ◽  
Liver Regeneration ◽  
Time Dependence ◽  
Thymidine Kinase ◽  
Partial Hepatectomy ◽  
Dna Content ◽  
Thymidylate Synthetase ◽  
High Dose ◽  
Regenerating Liver ◽  
Relative Contribution

1. Thyroparathyroidectomy (TPTX) carried out at 72 h before partial hepatectomy (PH) reduced the induction of hepatic thymidylate synthetase (TS) and thymidine kinase (TK), which are rate-determining enzymes in DNA synthesis, at 24 h after PH. 2. When TPTX was carried out at 24 h before PH, TK activity at 24 h after PH was not reduced at all, yet TS activity was reduced significantly. Thus the effect of TPTX differed in time dependence between TS and TK. 3. The depression of TK activity in rats which were subjected to TPTX at 72 h before PH, was recovered by Ca2+ supplementation. This result demonstrated that the rise of TK activity in regenerating liver is regulated by plasma Ca2+. 4. Since a high dose of tri-iodothyronine (T3) was required to cause elevation of the activities of these enzymes and DNA content in 24 h-regenerating liver of TPTX rats, the relative contribution of T3 to liver regeneration may be small.

Restriction of gut-derived endotoxin impairs DNA synthesis for liver regeneration

1985 ◽  
Vol 249 (5) ◽  
pp. R563-R569 ◽  
Author(s):  
R. P. Cornell
Keyword(s):  
Liver Resection ◽  
Dna Synthesis ◽  
Liver Regeneration ◽  
Partial Hepatectomy ◽  
Lipid A ◽  
Subcutaneous Administration ◽  
Endotoxin Tolerance ◽  
Polymyxin B ◽  
Gram Negative Bacteria ◽  
Higher Doses

The influence of restricting gut-derived endotoxin availability on liver regeneration after partial hepatectomy was evaluated. Partial hepatectomy was performed by 67% liver resection of ether-anesthetized rats. Liver regeneration was quantified after partial hepatectomy by [3H]thymidine incorporation into hepatic DNA; endotoxemia due to absorption of endogenous endotoxin from the gut into the portal circulation was determined by qualitative lysate assay of perchloric acid-extracted plasma samples, and plasma levels of the hepatotrophic factors insulin and glucagon were measured by radioimmunoassay. Treatments to restrict gut-derived endotoxin included chronic gavage with neomycin and cefazolin for gut sterilization, chronic gavage with cholestyramine to bind endotoxin within the gut, subcutaneous administration of polymyxin B to neutralize the lipid A portion of circulating endotoxin, intraperitoneal induction of endotoxin tolerance by progressively higher doses of endotoxin, and experimentation with isolator-reared defined flora Fisher rats that were Gram-negative bacteria deficient and therefore endotoxin deficient. All treatments to restrict endogenous endotoxin impaired DNA synthesis in regenerating livers particularly 21 h posthepatectomy when replication was increasing most rapidly in normal rats. We hypothesize that impairment of DNA synthesis after partial hepatectomy in endotoxin-restricted animals was due to the observed lack of normal systemic endotoxemic as well as hyperinsulinemic and hyperglucagonemic responses to 67% liver resection.

Stimulation of DNA synthesis in hepatocytes by kupffer cells after partial hepatectomy

Hepatology ◽  
1989 ◽  
Vol 9 (3) ◽  
pp. 405-410 ◽  
Author(s):  
Fujio Katsumoto ◽  
Kohji Miyazaki ◽  
Fumio Nakayama
Keyword(s):  
Dna Synthesis ◽  
Partial Hepatectomy ◽  
Kupffer Cells ◽  
Stimulation Of

Minoxidil, a KATPchannel opener, accelerates DNA synthesis following partial hepatectomy in rats

BioFactors ◽  
2005 ◽  
Vol 23 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Keiichi Yamasaki ◽  
Shigekazu Takemura ◽  
Yukiko Minamiyama ◽  
Seikan Hai ◽  
Satoshi Yamamoto ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Partial Hepatectomy

Influence of epidermal growth factor on liver regeneration after partial hepatectomy in mice

1991 ◽  
Vol 128 (3) ◽  
pp. 425-431 ◽  
Author(s):  
S. Noguchi ◽  
Y. Ohba ◽  
T. Oka
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Dna Synthesis ◽  
Liver Regeneration ◽  
Partial Hepatectomy ◽  
Dna Content ◽  
Sharp Peak ◽  
Submandibular Glands ◽  
Total Liver ◽  
Epidermal Growth

ABSTRACT The role of epidermal growth factor (EGF) in liver regeneration was studied in mice after partial hepatectomy. Two weeks before partial hepatectomy, mice were sham-operated (control) or sialoadenectomized (removal of submandibular glands) to reduce plasma EGF levels. Sialoadenectomized mice showed low plasma EGF levels (29·7 ±6·6 pmol/l; mean ± s.e.m.) compared with controls (66·0±8·3 pmol/l). After partial hepatectomy, sialoadenectomized mice were treated with or without a daily s.c. injection of 5 μg EGF and the rate of DNA synthesis in the regenerating liver was monitored by [125I]iododeoxyuridine uptake. Control mice showed a sharp peak of DNA synthesis at 48 h after partial hepatectomy while sialoadenectomized mice showed a delayed and broad peak at 84 h. Treatment of sialoadenectomized mice with EGF (5 μg/mouse per day) completely restored the pattern of DNA synthesis so that a sharp peak appeared at 48 h. The total liver DNA content of the control mice (79·1±2·5% of the preoperative level; mean ± s.e.m.) was significantly (P < 0·01) higher than that of the sialoadenectomized mice (65·2±3·0%) 3 days after partial hepatectomy, but this difference disappeared on day 7 when liver regeneration was almost completed in both groups. Treatment of sialoadenectomized mice with EGF increased total liver DNA content (78·2±2·9%) to that of control mice on day 3 after partial hepatectomy. In addition, normal mice showed a rapid increase in plasma EGF levels at 1–8 h after partial hepatectomy, whereas sialoadenectomized mice showed low plasma EGF levels throughout the course of the experiment. These results suggest that EGF derived from the submandibular glands plays a role in promoting the early stage of liver regeneration. Journal of Endocrinology (1991) 128, 425–431

Impaired Ras membrane association and activation in PPARα knockout mice after partial hepatectomy

2003 ◽  
Vol 284 (2) ◽  
pp. G302-G312 ◽  
Author(s):  
Michael D. Wheeler ◽  
Olivia M. Smutney ◽  
Jennifer F. Check ◽  
Ivan Rusyn ◽  
R. Schulte-Hermann ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Dna Synthesis ◽  
Partial Hepatectomy ◽  
Cell Cycle Progression ◽  
Small Gtpases ◽  
Membrane Association ◽  
Peroxisome Proliferator ◽  
Wild Type ◽  
Peroxisome Proliferator Activated Receptor ◽  
Key Events

Liver regeneration after partial hepatectomy (PH) involves several signaling mechanisms including activation of the small GTPases Ras and RhoA in response to mitogens leading to DNA synthesis and cell proliferation. Peroxisome proliferator-activated receptor-α (PPARα) regulates the expression of several key enzymes in isoprenoid synthesis, which are key events for membrane association of Ras and RhoA. Thus the role of PPARα in cell proliferation after PH was tested. After PH, an increase in PPARα DNA binding was observed in wild-type mice, correlating with an increase in the PPARα-regulated enzyme acyl-CoA oxidase. In addition, the PPARα-regulated genes farnesyl pyrophosphate synthase and 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) synthase were significantly increased in wild-type mice. However, these increases were not observed in PPARα knockout (PPARα −/−) mice. The peak in DNA synthesis observed 42 h after PH was reduced by ∼60% in PPARα −/− mice, despite increases in TNF-α and IL-1. Also, under these conditions, membrane association of Ras was high in wild-type mice after PH but was impaired in PPARα −/− mice. Accordingly, Ras was significantly elevated in the cytosol in PPARα −/− mice. This observation correlated with lower levels of active GTP-bound Ras after PH in PPARα −/− mice compared with wild-type mice. Similar observations were made for RhoA. Moreover, deletion of PPARα blunted the activation of cyclin-dependent kinase (cdk)2/cyclin E and cdk4/cyclin D complexes. Collectively, these results support the hypothesis that PPARα is necessary for cell cycle progression in regenerating mouse liver via mechanisms involving prenylation of small GTPases Ras and RhoA.

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