Stimulation of proliferative activity of liver cells of intact mice by lymphocytes of partially hepatectomized donors

1969 ◽  
Vol 68 (1) ◽  
pp. 788-791 ◽  
Author(s):  
A. G. Babaeva ◽  
N. A. Kraskina ◽  
L. D. Liozner
Keyword(s):  
Proliferative Activity ◽  
Liver Cells ◽  
Stimulation Of

scholarly journals The role of insulin in the modulation of glucagon-dependent control of phenylalanine hydroxylation in isolated liver cells

1987 ◽  
Vol 242 (3) ◽  
pp. 655-660 ◽  
Author(s):  
M J Fisher ◽  
A J Dickson ◽  
C I Pogson
Keyword(s):  
Cyclic Amp ◽  
Insulin Action ◽  
Phenylalanine Hydroxylase ◽  
Liver Cells ◽  
Phosphorylation State ◽  
Isolated Liver Cells ◽  
The Impact ◽  
Isolated Liver ◽  
Stimulation Of

The stimulation of phenylalanine hydroxylation in isolated liver cells by sub-maximally effective concentrations of glucagon (less than 0.1 microM) is antagonized by insulin (0.1 nM-0.1 microM). This phenomenon is a consequence of a decrease in the glucagon-stimulated phosphorylation of phenylalanine hydroxylase from liver cells incubated in the presence of insulin. The impact of insulin on the phosphorylation state and activity of the hydroxylase is mimicked by incubation of liver cells in the presence of orthovanadate (10 microM). A series of cyclic AMP and cyclic GMP analogues enhanced phenylalanine hydroxylation: in each case insulin diminished the stimulation of flux. These results are discussed in the light of the characteristics of insulin action on other metabolic processes.

scholarly journals Effect of treatment in vivo of rats with bacterial endotoxin on fructose 2,6-bisphosphate metabolism and L-pyruvate kinase activity and flux in isolated liver cells

1992 ◽  
Vol 284 (3) ◽  
pp. 761-766 ◽  
Author(s):  
E D Ceppi ◽  
R G Knowles ◽  
K M Carpenter ◽  
M A Titheradge
Keyword(s):  
Pyruvate Kinase ◽  
Intact Cell ◽  
Total Activity ◽  
Liver Cells ◽  
Bacterial Endotoxin ◽  
Phosphorylation State ◽  
Isolated Liver Cells ◽  
Effect Of Treatment ◽  
Isolated Liver ◽  
Stimulation Of

The effect of treatment of rats with bacterial endotoxin on fructose 2,6-bisphosphate (Fru-2,6-P2) metabolism was investigated in isolated liver cells prepared from 18 h-starved animals. The results obtained support the hypothesis that a stimulation of 6-phosphofructo-1-kinase (PFK-1) activity and an inhibition of fructose-1,6-bisphosphatase (Fru-1,6-P2ase) may be one mechanism underlying the inhibition of gluconeogenesis from lactate and pyruvate by endotoxin. We suggest that the stimulation of PFK-1 and inhibition of Fru-1,6-P2ase activity is the result of a 2-3-fold increase in Fru-2,6-P2. The latter is not due to changes in the total activity or phosphorylation state of the bifunctional 6-phosphofructo-2-kinase (PFK-2)/fructose-2,6-bisphosphatase, but appears to be the result of a decrease in the cytosolic concentration of phosphoenolpyruvate (PEP), an inhibitor of PFK-2 activity. The effect of endotoxin is resistant to the presence of glucagon, which has comparable effects in cells prepared from both control and endotoxin-treated animals. The mechanism by which endotoxin treatment of the rat decreases PEP and gluconeogenesis remains to be established. However, it does not involve alterations in either the total activity or the phosphorylation state of pyruvate kinase, nor does it involve increased flux through this enzyme in the intact cell, which is in fact decreased in this model of septic shock. It is suggested that the decreased flux may result from a lower rate of formation of PEP, suggesting that the prime lesion in sepsis is an inhibition of one or more of the steps leading to PEP formation.

scholarly journals The characteristics and site of inhibition of gluconeogenesis in rat liver cells by bacterial endotoxin. Stimulation of phosphofructokinase-1

1987 ◽  
Vol 242 (3) ◽  
pp. 721-728 ◽  
Author(s):  
R G Knowles ◽  
J P McCabe ◽  
S J Beevers ◽  
C I Pogson
Keyword(s):  
Enzyme Activities ◽  
Pyruvate Carboxylase ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Liver Cells ◽  
Atp Content ◽  
Rat Liver Cells ◽  
Endogenous Substrates ◽  
And Control ◽  
Control Coefficients ◽  
Stimulation Of

The characteristics and site of inhibition of gluconeogenesis by endotoxin were investigated in liver cells isolated from control and endotoxin-treated rats. Endotoxin treatment was associated with inhibition (40-50%) of gluconeogenesis from lactate plus pyruvate over a range of concentrations of substrate and of oleate and with or without glucose or glucagon. Similar inhibition was observed with asparagine, proline, glutamine, alanine and a substrate mixture, but not with glycerol, glyceraldehyde, dihydroxyacetone or endogenous substrates. There was no change in cellular ATP content or in the rates of ketogenesis or ureogenesis from asparagine, proline or glutamine. Other effects on isotopic fluxes, metabolite contents, enzyme activities and control coefficients were consistent with the suggestion that the effects of endotoxin on gluconeogenesis are exerted at the level of phosphofructokinase-1, and not at phosphoenolpyruvate carboxykinase, pyruvate kinase, pyruvate carboxylase or glucokinase.

scholarly journals Cyclo-oxygenase 2 expression impairs serum-withdrawal-induced apoptosis in liver cells

2006 ◽  
Vol 398 (3) ◽  
pp. 371-380 ◽  
Author(s):  
Amalia Fernández-Martínez ◽  
Belén Mollá ◽  
Rafael Mayoral ◽  
Lisardo Boscá ◽  
Marta Casado ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Liver Cells ◽  
Cell Cycle Distribution ◽  
Hepatitis C Infection ◽  
Extrinsic Pathway ◽  
Akt Phosphorylation ◽  
Liver Cancers ◽  
Cox 2 ◽  
Stimulation Of

We have investigated the mechanism of COX-2 (cyclo-oxygenase 2)-dependent inhibition of apoptosis in liver, a key pathway underlying proliferative actions of COX-2 in liver cancers, cirrhosis, chronic hepatitis C infection and regeneration after partial hepatectomy. Stable expression of COX-2 in CHL (Chang liver) cells induced proliferation, with an increase in the proportion of cells in S-phase, but no other significant changes in cell-cycle distribution. This was associated with a marked inhibition of the apoptotic response to serum deprivation, an effect mimicked by treating empty-vector-transfected control cells (CHL-V cells) with prostaglandin E2 and prevented in COX-2-expressing cells (CHL-C cells) treated with selective inhibitors of COX-2. Serum-deprived CHL-V cells displayed several indicators of activation of intrinsic apoptosis: caspases 9 and 3 activated within 6 h and caspase 8 within 18 h, Bax expression was induced, cytochrome c was released to the cytosol, and PARP-1 [poly(ADP-ribose) polymerase 1] cleavage was evident in nuclei. COX-2 expression blocked these events, concomitant with reduced expression of p53 and promotion of Akt phosphorylation, the latter indicating activation of survival pathways. CHL cells were resistant to stimulation of the extrinsic pathway with anti-Fas antibody. Moreover, in vivo expression of GFP (green fluorescent protein)-labelled COX-2 in mice by hydrodynamics-based transient transfection conferred resistance to caspase 3 activation and apoptosis induced by stimulation of Fas.

scholarly journals The effects of added purines on urate and purine synthesis de novo by isolated chick liver, kidney and lymphoid cells

1976 ◽  
Vol 158 (3) ◽  
pp. 549-556 ◽  
Author(s):  
P Badenoch-Jones ◽  
P J Buttery
Keyword(s):  
De Novo ◽  
Cell Types ◽  
Liver Cells ◽  
Lymphoid Cells ◽  
Kidney Cells ◽  
Purine Synthesis ◽  
Liver And Kidney ◽  
Stimulation Of

1. Isolated chick lymphoid cells, together with isolated chick liver and kidney cells, incorporate [1-14C]glycine or [14C]formate into urate. 2. Of the cell types used, bursal cells incorporate 14C into urate at the fastest rate, although the output of total urate by bursal cells is only 10% that of liver cells. 3. When suspended in Eagle's medium the incorporation of 14C into urate is inhibited by adenine and guanine up to 1 mM. In contrast, the addition of 1 mM-AMP or -GMP results in a relatively large stimulation of this incorporation. 4. Added adenine is rapidly taken up by liver cells and then released in an unmetabolized form; AMP is taken up more slowly and is rapidly metabolized. The metabolites (possibly including adenine) are then released. 5. Intracellular liver 5-phosphoribosyl 1-pyrophosphate is approx. 0.7mM and remains constant or falls slightly during a 3 h incubation of the cells. 6. The addition of adenine or guanine, AMP or GMP, does not alter liver intracellular 5-phosphoribosyl 1-pyrophosphate concentrations. Added 5-phosphoribosyl 1-pyrophosphate is not taken up by liver cells. 7. The results are discussed in the context of the control of urate and purine synthesis de novo in the chick.

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