scholarly journals Characterization of the binding of diadenosine 5′,5‴-P1,P4-tetraphosphate (Ap4A) to rat liver cell membranes

1996 ◽  
Vol 314 (2) ◽  
pp. 687-693 ◽  
Author(s):  
Mandy EDGECOMBE ◽  
Alexander G. McLENNAN ◽  
Michael J. FISHER
Keyword(s):  
Plasma Membrane ◽  
Rat Liver ◽  
Liver Cell ◽  
Plasma Membranes ◽  
Rank Order ◽  
Liver Cells ◽  
Diadenosine Polyphosphates ◽  
Cell Plasma ◽  
Isolated Liver Cells ◽  
Isolated Liver

Diadenosine polyphosphates present in the extracellular environment can, through interaction with appropriate purinoceptors, influence a range of cellular activities. Here we have investigated the nature of the ligand:receptor interactions involved in diadenosine 5′,5″-P1,P4-tetraphosphate (Ap4A)-mediated stimulation of glycogen breakdown in isolated rat liver cells. [2-3H]Ap4A showed specific binding to both intact isolated liver cells and plasma membrane fractions prepared from isolated liver cells. HPLC analysis confirmed that binding was mediated by intact Ap4A and not by potential breakdown products (e.g. ATP, adenosine etc). Binding of [2-3H]Ap4A, to isolated liver cell plasma membrane preparations, was successfully displaced by a range of both naturally occurring and synthetic diadenosine polyphosphates with the rank order potency Ap4A ⩾Ap5A > Ap6A > Ap3A > Ap2A. [2-3H]Ap4A binding was not displaced by P1 effectors but was successfully displaced by a range of P2 effectors with the rank order potency 2-methylthio-ATP > ATP > ADP ⩾adenosine 5′-[αβ-methylene]triphosphate > adenosine 5′-[βγ-methylene]triphosphate. These findings are consistent with the interaction of Ap4A with a P2y-like subclass of purinoceptor and are discussed in relation to (1) the known purinoceptor populations in liver cell plasma membranes and (2) observations concerning the binding of diadenosine polyphosphates to purinoceptors in other tissues.

Fractionation of isolated liver cells after disruption with a nitrogen bomb and sonication

1982 ◽  
Vol 57 (1) ◽  
pp. 1-13
Author(s):  
F. Autuori ◽  
U. Brunk ◽  
E. Peterson ◽  
G. Dallner
Keyword(s):  
Rat Liver ◽  
Sucrose Gradient ◽  
Divalent Cations ◽  
Liver Cells ◽  
Cell Disruption ◽  
Isolated Liver Cells ◽  
Discontinuous Sucrose Gradient ◽  
Microsomal Membranes ◽  
Isolated Liver

Hepatocytes from rat liver were prepared by perfusion with collagenase, and rough and smooth microsomes and mitochondria were prepared after cell disruption. By applying 1000 lb/in2 (1 lb/in2 = 6.9 kPa) in a nitrogen bomb followed by decompression, 75% of the cells were disrupted after four consecutive treatments. Intact mitochondria, and rough and smooth microsomes with little contamination were prepared from the homogenate. A more rapid disruption was attained by a short sonication with a low output, thus increasing the efficiency of homogenization. The microsomal subfractions prepared from this homogenate were comparable to those obtained after decompression. Sonication resulted in smooth microsomes, which exhibited a higher contamination with non-microsomal membranes. These, however, were partly removed by additional centrifugation with a discontinuous sucrose gradient containing divalent cations.

scholarly journals Polyribosomes in isolated liver cells. Preparative procedures, effects of incubation and correlation with protein synthesis

1980 ◽  
Vol 186 (1) ◽  
pp. 35-45 ◽  
Author(s):  
A J Dickson ◽  
C I Pogson
Keyword(s):  
Protein Synthesis ◽  
Rat Liver ◽  
Isolated Hepatocytes ◽  
Liver Cells ◽  
Liver Protein ◽  
Isolated Cells ◽  
Isolated Liver Cells ◽  
Rat Liver Cells ◽  
Isolated Liver

Methods have been derived which permit the isolation of undergraded polyribosomes from isolated rat liver cells. Under the conditions used the polyribosome profile of hepatocytes immediately after isolation was essentially identical with that from intact liver. However, during incubation of cells in complex physiological media there was a progressive dissociation of polyribosomes. The addition of a variety of factors that produce reaggregation of polyribosomes in rat liver in vivo did not prevent dissociation during cell incubations. Although large polyribosomes were lost most rapidly, the albumin-synthesizing capacity of isolated cells was not selectively lost when compared with total protein synthesis. The significance of these results for the use of isolated hepatocytes in the study of liver protein synthesis is discussed.

Characterization of Rat Liver Cell Plasma Membranes

1975 ◽  
Vol 150 (1) ◽  
pp. 177-184 ◽  
Author(s):  
M. M. Fisher ◽  
D. L. Bloxam ◽  
M. Oda ◽  
M. J. Phillips ◽  
I. M. Yousef
Keyword(s):  
Rat Liver ◽  
Liver Cell ◽  
Plasma Membranes ◽  
Cell Plasma

Plasma membranes from isolated liver cells

1972 ◽  
Vol 274 (2) ◽  
pp. 631-637 ◽  
Author(s):  
Antal Solyom ◽  
Carl J. Lauter ◽  
Eberhard G. Trams
Keyword(s):  
Plasma Membranes ◽  
Liver Cells ◽  
Isolated Liver Cells ◽  
Isolated Liver

Alteration in D-Glucose Uptake by Plasma Membranes of Isolated Liver Cells

1978 ◽  
Vol 359 (1) ◽  
Author(s):  
Werner Bachmann ◽  
Ralph Jersild ◽  
David Challoner
Keyword(s):  
Glucose Uptake ◽  
Plasma Membranes ◽  
Liver Cells ◽  
Isolated Liver Cells ◽  
Isolated Liver

scholarly journals The role of haem in the regulation of rat liver tryptophan metabolism

1986 ◽  
Vol 240 (1) ◽  
pp. 259-263 ◽  
Author(s):  
M Salter ◽  
C I Pogson
Keyword(s):  
Rat Liver ◽  
Intraperitoneal Injection ◽  
Liver Cells ◽  
Tryptophan Metabolism ◽  
Isolated Liver Cells ◽  
Tryptophan Oxidation ◽  
Isolated Liver

At saturating concentrations of tryptophan, the activity of tryptophan 2,3-dioxygenase was the same in isolated liver cells and in extracts with added haematin. Intraperitoneal injection of haematin did not increase tryptophan oxidation in livers subsequently perfused in situ. Preincubation of liver cells with physiological concentrations of tryptophan caused maximal saturation of tryptophan 2,3-dioxygenase with haem in liver cells. In cell-free extracts tryptophan 2,3-dioxygenase exhibited complex kinetics with haem. The results have important implications for the understanding of the role of haem in tryptophan metabolism.

Titration of Rat Liver with Digitonin: a Well Defined Short Term Damage of Cellular Metabolism

1981 ◽  
Vol 36 (9-10) ◽  
pp. 880-883 ◽  
Author(s):  
Stefan Postius ◽  
Dieter Platt
Keyword(s):  
Lactate Dehydrogenase ◽  
Rat Liver ◽  
Liver Cell ◽  
Plasma Membranes ◽  
Short Term ◽  
Isolated Rat Liver ◽  
Physiological Conditions ◽  
Cell Plasma ◽  
Molecular Compounds ◽  
Isolated Rat

Abstract Carefully performed pulse titration of the isolated rat liver in the course of continuous erythro­ cyte free perfusion with small amounts of digitonin causes a short term perm eability of liver cell plasma membranes with concomitant short lived release of intracellular low or high molecular compounds such as ATP or lactate dehydrogenase. Gluconeogenesis from lactate being completely inhibited during this period restores w ithin about one m inute up to a level that depends on the am ount of perfused digitonin. The described experimental m odel is suggested to be useful for the measurement of cytoplasmic m etabolites under physiological conditions. It moreover offers the possibility to im port foreign substances into liver cells th at normally do not penetrate liver cell plasma membranes.

Sign in / Sign up

Export Citation Format

Share Document