scholarly journals Phosphatidylcholine metabolism in rat liver after partial hepatectomy. Evidence for increased activity and amount of CTP:phosphocholine cytidylyltransferase

1991 ◽  
Vol 278 (2) ◽  
pp. 347-351 ◽  
Author(s):  
M Houweling ◽  
L B M Tijburg ◽  
H Jamil ◽  
D E Vance ◽  
C B Nyathi ◽  
...  
Keyword(s):  
Partial Hepatectomy ◽  
Rat Liver ◽  
Sham Operation ◽  
Ctp:Phosphocholine Cytidylyltransferase ◽  
Enzyme Molecules ◽  
Increased Activity ◽  
Phosphatidylcholine Metabolism ◽  
Control Sham ◽  
Stimulation Of

The effect of partial (70%) hepatectomy on phosphatidylcholine (PC) synthesis in rat liver was investigated during the first 4 post-operative days. Between 4 and 96 h after partial hepatectomy, the mass of PC increased from 30% to 80% of sham-operation values, being comparable with the restoration of total liver mass after partial hepatectomy. Relative to control (sham-operation), the incorporation in vivo of [3H]choline into PC was stimulated 2.6-fold at 22 h after partial hepatectomy. Moreover, CTP:phosphocholine cytidylyltransferase (EC 2.7.7.15) activity was significantly enhanced, and the pool size of phosphocholine decreased at 22 and 48 h after partial hepatectomy, whereas the activity of choline kinase (EC 2.7.1.32) was augmented at a later stage of liver regeneration (48 and 96 h). Stimulation of CTP:phosphocholine cytidylyltransferase activity by partial hepatectomy occurred in both the microsomal and cytosolic fractions. The stimulatory effect in the cytosolic fraction was mainly due to an increase in the number of enzyme molecules, as demonstrated by immunotitration of the amount of cytosolic cytidylyltransferase protein.

scholarly journals Phosphatidylethanolamine metabolism in rat liver after partial hepatectomy. Control of biosynthesis of phosphatidylethanolamine by the availability of ethanolamine

1992 ◽  
Vol 283 (1) ◽  
pp. 55-61 ◽  
Author(s):  
M Houweling ◽  
L B M Tijburg ◽  
W J Vaartjes ◽  
L M G van Golde
Keyword(s):  
Partial Hepatectomy ◽  
Rat Liver ◽  
Sham Operation ◽  
Regenerating Liver ◽  
Ethanolamine Kinase ◽  
Time Period

The effect of partial (70%) hepatectomy on phosphatidylethanolamine (PE) synthesis was studied in rat liver during the first 4 post-operative days. Between 4 and 96 h after partial hepatectomy, the mass of PE increased from 30% to 80% of sham-operation values. In line with the increase in PE mass, the rate of PE synthesis in vivo from [14C]ethanolamine was stimulated 1.6- and 1.3-fold at 22 and 48 h after partial hepatectomy respectively. Surprisingly, the activity of CTP:phosphoethanolamine cytidylyltransferase (EC 2.7.7.14) was virtually unchanged after partial hepatectomy. In addition, neither ethanolamine kinase (EC 2.7.1.82) nor ethanolaminephosphotransferase (EC 2.7.8.1) showed any changes in activity over the time period studied. Hepatic levels of ethanolamine and phosphoethanolamine were drastically increased after partial hepatectomy, as compared with sham operation, whereas levels of CDP-ethanolamine and microsomal diacylglycerol were not affected. Interestingly, partial hepatectomy caused the concentration of free ethanolamine in serum to increase from 29 microM to approx. 50 microM during the first day after surgery. In hepatocytes isolated from non-operated animals, incorporation of [3H]ethanolamine into PE was stimulated by increasing the ethanolamine concentration from 10 up to 50 microM, whereas the radioactivity associated with phosphoethanolamine only increased at ethanolamine concentrations higher than 30 microM. Taken together, our results indicate that the observed increase in serum ethanolamine concentration after partial hepatectomy is probably responsible for both the increase in PE biosynthesis and the accumulation of ethanolamine and phosphoethanolamine in regenerating 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 Biotin-mediated protein biosynthesis

1974 ◽  
Vol 140 (3) ◽  
pp. 549-556 ◽  
Author(s):  
R. L. Boeckx ◽  
K. Dakshinamurti
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Rat Liver ◽  
Intestinal Mucosa ◽  
Protein Biosynthesis ◽  
Amino Acid Incorporation ◽  
Acid Incorporation ◽  
Stimulation Of

The effect of administration of biotin to biotin-deficient rats on protein biosynthesis was studied. Biotin treatment resulted in stimulation by more than twofold of amino acid incorporation into protein, both in vivo and in vitro in rat liver, pancreas, intestinal mucosa and skin. Analysis of the products of amino acid incorporation into liver proteins in vivo and in vitro indicated that the synthesis of some proteins was stimulated more than twofold, but others were not stimulated at all. This indicates a specificity in the stimulation of protein synthesis mediated by biotin.

scholarly journals Thymidine metabolism in regenerating rat liver one to two hours after partial hepatectomy

1973 ◽  
Vol 136 (3) ◽  
pp. 571-577 ◽  
Author(s):  
Margery G. Ord ◽  
Lloyd A. Stocken
Keyword(s):  
Partial Hepatectomy ◽  
Intravenous Injection ◽  
Rat Liver ◽  
Thymidine Uptake ◽  
Regenerating Rat Liver ◽  
Perfusion Studies ◽  
Saturation Kinetics

1. When [3H]thymidine was injected intravenously into rats in amounts up to 40mg/kg body wt. and the3H radioactivity in the livers measured at 30min, saturation kinetics for thymidine uptake were not found. If the animals were examined 3 min after intravenous injection, saturation could be attained in normal rats with 12mg of thymidine/kg and in partially hepatectomized rats with 4mg/kg. At concentrations of thymidine close to saturation, no differences were found in rate or amount of uptake/g of liver between normal and partially hepatectomized rats 1–2h after operation. 2. Perfusion techniques were used to compare thymidine uptakes in the two sets of rats at concentrations up to 40μm-thymidine. Uptakes with tracer amounts of thymidine after 30min were identical in vivo and in the perfusion studies and were twice as great in livers from partially hepatectomized rats with concentrations up to 40μm-thymidine. 3. At 1.5h after operation there was nearly twice as much β-aminoisobutyrate present per g of liver from partially hepatectomized as compared with normal rats.

scholarly journals Metabolism of ornithine, α-ketoglutarate and arginine in isolated perfused rat liver

1995 ◽  
Vol 73 (2) ◽  
pp. 227-239 ◽  
Author(s):  
Jean Pascal De Bandt ◽  
Luc Cynober ◽  
Soo Kyung Lim ◽  
Colette Coudray-Lucas ◽  
Raoul Poupon ◽  
...  
Keyword(s):  
Rat Liver ◽  
Hepatic Metabolism ◽  
Isolated Perfused Rat Liver ◽  
Trauma Patients ◽  
Perfused Rat Liver ◽  
Metabolic Interaction ◽  
Urea Production ◽  
Stimulation Of

Ornithine (Orn; α-ketoglutarate (αKG) salt) and arginine (Arg) supplementation of enteral diets has been advocated in the treatment of hypercatabolism of trauma patients, but both compounds are subject to extensive hepatic metabolism. To compare the metabolism of these two compounds and to evaluate the possible influence of the αKG moiety, livers were perfused with αKG, Orn, ornithine α-ketoglutarate (OKG) or Arg (n 6 in each group) for 1 h. Arg uptake was nearly fourfold higher than Orn uptake (690 (SD 162) ν. 178 (SD 30) nmol/min per g liver), and Orn uptake was not modified by αKG. Orn was totally metabolized by the liver, whereas Arg led to Orn release (408 (SD 159) nmol/min per g liver) and a threefold stimulation of urea production (Arg 1·44 (SD 0·22) ν. Orn 0·45 (SD 0.09) μol/min per g liver). αKG alone only increased hepatic aspartate uptake but, when associated with Orn as OKG, it led to an increase in giutamate release and in proiine content in the liver and to a decrease in proiine uptake. From these findings we conclude that (1) Arg load is extensively metabolized by the liver, inducing urea production, (2) in enteral use, Orn supplementation appears preferable to Arg as it is less ureogenic (as also recently demonstrated in vivo in stressed rats receiving isomolar amounts of Arg and Orn), (3) the liver participates in the Orn-αKG metabolic interaction, mostly in proiine metabolism, which occurs in the splanchnic area.

In vitro stimulation of rat liver cells by homologous partial hepatectomy serum

In Vitro ◽  
1971 ◽  
Vol 7 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Lynne P. Rutzky ◽  
William G. Taylor ◽  
Robert W. Pumper
Keyword(s):  
Partial Hepatectomy ◽  
Rat Liver ◽  
Liver Cells ◽  
Rat Liver Cells ◽  
Stimulation Of

Stimulation of putrescine production by epidermal growth factor in rat liver after partial hepatectomy

Hepatology ◽  
1991 ◽  
Vol 14 (5) ◽  
pp. 901-905 ◽  
Author(s):  
Sumiko Nagoshi ◽  
Tomoaki Tomiya ◽  
Yuzuru Sato ◽  
Yuji Oka ◽  
Itsuro Ogata ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Partial Hepatectomy ◽  
Rat Liver ◽  
Epidermal Growth ◽  
Stimulation Of
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