scholarly journals Effects of taurolithocholate, a Ca2+-mobilizing agent, on cell Ca2+ in rat hepatocytes, human platelets and neuroblastoma NG108-15 cell line

1991 ◽  
Vol 273 (1) ◽  
pp. 153-160 ◽  
Author(s):  
J F Coquil ◽  
B Berthon ◽  
N Chomiki ◽  
L Combettes ◽  
P Jourdon ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Bile Acid ◽  
Cell Line ◽  
Rat Liver ◽  
Neuronal Cell ◽  
Rat Hepatocytes ◽  
Cell Types ◽  
Liver Cells ◽  
Human Platelets ◽  
Rat Liver Cells

The monohydroxy bile acid taurolithocholate permeabilizes the endoplasmic reticulum to Ca2+ in rat liver cells. To assess whether this action on the endoplasmic reticulum was restricted to this tissue, the effects of bile acid were investigated in two cell types quite unrelated to rat hepatocyte, namely human platelets and neuronal NG108-15 cell line. The results showed that taurolithocholate (3-100 microM) had no effect on free cytosolic [Ca2+] in human platelets and NG108-15 cells. whereas it increased it from 180 to 520 nM in rat hepatocytes. In contrast, in cells permeabilized by saponin, taurolithocholate initiated a profound release of the stored Ca2+ from the internal Ca2+ pools in the three cell types. The bile acid released 90% of the Ca2+ pools, with rate constants of about 5 min-1 and half-maximal effects at 15-30 microM. The results also showed that, in contrast with liver cells, which displayed an influx of [14C]taurolithocholate of 2 nmol/min per mg, human platelets and the neuronal cell line appeared to be resistant to [14C]taurolithocholate uptake. The influx measured in these latter cells was about 100-fold lower than in rat liver cells. Taken together, these data suggest that human platelets and NG108-15 cells do not possess the transport system for concentrating monohydroxy bile acids into cells. However, they show that human platelets and neuronal NG108-15 possess, in common with liver cells, the intracellular system responsible for taurolithocholate-mediated Ca2+ release from internal stores.

scholarly journals Arachidonic acid inhibits the store-operated Ca2+ current in rat liver cells

2005 ◽  
Vol 385 (2) ◽  
pp. 551-556 ◽  
Author(s):  
Grigori Y. RYCHKOV ◽  
Tom LITJENS ◽  
Michael L. ROBERTS ◽  
Greg J. BARRITT
Keyword(s):  
Arachidonic Acid ◽  
Rat Liver ◽  
Membrane Conductance ◽  
Rat Hepatocytes ◽  
Cell Types ◽  
Receptor Activation ◽  
Liver Cells ◽  
H4iie Cells ◽  
Rat Liver Cells ◽  
Ca2 Channels

Vasopressin and other phospholipase-C-coupled hormones induce oscillations (waves) of [Ca2+]cyt (cytoplasmic Ca2+ concentration) in liver cells. Maintenance of these oscillations requires replenishment of Ca2+ in intracellular stores through Ca2+ inflow across the plasma membrane. While this may be achieved by SOCs (store-operated Ca2+ channels), some studies in other cell types indicate that it is dependent on AA (arachidonic acid)-activated Ca2+ channels. We studied the effects of AA on membrane conductance of rat liver cells using whole-cell patch clamping. We found no evidence that concentrations of AA in the physiological range could activate Ca2+-permeable channels in either H4IIE liver cells or rat hepatocytes. However, AA (1–10 μM) did inhibit (IC50=2.4±0.1 μM) Ca2+ inflow through SOCs (ISOC) initiated by intracellular application of Ins(1,4,5)P3 in H4IIE cells. Pre-incubation with AA did not inhibit ISOC development, but decreased maximal amplitude of the current. Iso-tetrandrine, widely used to inhibit receptor-activation of phospholipase A2, and therefore AA release, inhibited ISOC directly in H4IIE cells. It is concluded that (i) in rat liver cells, AA does not activate an AA-regulated Ca2+-permeable channel, but does inhibit SOCs, and (ii) iso-tetrandrine and tetrandrine are effective blockers of CRAC (Ca2+-release-activated Ca2+) channel-like SOCs. These results indicate that AA-activated Ca2+-permeable channels do not contribute to hormone-induced increases or oscillations in [Ca2+]cyt in liver cells. However, AA may be a physiological modulator of Ca2+ inflow in these cells.

scholarly journals Release of calcium from the endoplasmic reticulum by bile acids in rat liver cells.

1988 ◽  
Vol 263 (5) ◽  
pp. 2299-2303 ◽  
Author(s):  
L Combettes ◽  
M Dumont ◽  
B Berthon ◽  
S Erlinger ◽  
M Claret
Keyword(s):  
Endoplasmic Reticulum ◽  
Bile Acids ◽  
Rat Liver ◽  
Liver Cells ◽  
Rat Liver Cells

Effect of Method of Cell Isolation on the Metabolic Activity of Isolated Rat Liver Cells

1972 ◽  
Vol 10 (1) ◽  
pp. 167-179
Author(s):  
L. G. LIPSON ◽  
D. M. CAPUZZI ◽  
S. MARGOLIS
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Cell Types ◽  
Liver Cells ◽  
Ultrastructural Changes ◽  
Acetate Incorporation ◽  
Amino Acid Incorporation ◽  
Acid Incorporation ◽  
Rat Liver Cells ◽  
Modified Enzyme

Rat liver cells isolated with a tissue press, by tetraphenylboron (TPB) chelation, or by hyaluronidase and collagenase digestion were compared as to morphology, cell yield, and biosynthetic activity. The cells were intact by light microscopy; ultrastructural changes were present on electron-microscopic examination of all cell types except those prepared by a modified enzyme incubation method. TPB chelation gave the largest and enzyme techniques the smallest yield of cells. All cell types incorporated labelled amino acids into cellular protein; however, amino acid incorporation was greatest in cells isolated by the revised enzyme technique. Only enzyme and mechanical cells incorporated acetate into cellular lipid. Cofactor supplementation was not required in the modified enzyme cells. Acetate incorporation was more sensitive to preincubation than was amino acid incorporation. Calcium, which was required to prevent aggregation of enzyme cells, inhibited amino acid incorporation moderately and acetate incorporation completely in mechanical cells.

scholarly journals Bile Acid Synthesis in Isolated Rat Liver Cells. The Effect of 7alpha-Hydroxycholesterol

1980 ◽  
Vol 103 (2) ◽  
pp. 299-305 ◽  
Author(s):  
Kathleen M. BOTHAM ◽  
Geoffrey J. BECKETT ◽  
Iain W. PERCY-ROBB ◽  
George S. BOYD
Keyword(s):  
Bile Acid ◽  
Rat Liver ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Liver Cells ◽  
Isolated Rat Liver ◽  
Rat Liver Cells ◽  
Isolated Rat

scholarly journals Differential effects of tryptophan on glucose synthesis in rats and guinea pigs

1978 ◽  
Vol 176 (3) ◽  
pp. 817-825 ◽  
Author(s):  
S A Smith ◽  
K R F Elliott ◽  
C I Pogson
Keyword(s):  
Rat Liver ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Glucose Production ◽  
Rat Hepatocytes ◽  
Liver Cells ◽  
Isolated Rat Hepatocytes ◽  
Rat Liver Cells ◽  
Glucose Output ◽  
Isolated Rat

1. Tryptophan inhibition of gluconeogenesis in isolated rat liver cells is characterized by a 20 min lag period before linear rates of glucose output are attained. 2. Half-maximal inhibition of gluconeogenesis in isolated rat hepatocytes is produced by approx. 0.1 mM-tryptophan. 3. Tryptophan inhibits gluconeogenesis from all substrates giving rise to oxaloacetate, but stimulates glycerol-fuelled glucose production. 4. Gluconeogenesis in guinea-pig hepatocytes is insensitive to tryptophan. 5. Changes in metabolite concentrations in rat liver cells are consistent with a locus of inhibition at the step catalysed by phosphoenolpyruvate carboxykinase. 6. Inhibition of gluconeogenesis persists in cells from rats pretreated with tryptophan in vivo. 7. Tryptophan has no effect on urea production from alanine, but decreases [1-14C]palmitate oxidation to 14CO2 and is associated with an increased [hydroxybutyrate]/[acetoacetate] ratio. 8. These results are discussed with reference to the control of gluconeogenesis in various species.

scholarly journals Evidence that poly(ADP-ribose) polymerase is involved in the loss of NAD from cultured rat liver cells

1982 ◽  
Vol 202 (2) ◽  
pp. 551-553 ◽  
Author(s):  
A J Paine ◽  
C M Allen ◽  
B W Durkacz ◽  
S Shall
Keyword(s):  
Dna Repair ◽  
Rat Liver ◽  
Mammalian Cells ◽  
Rat Hepatocytes ◽  
Differential Response ◽  
Liver Cells ◽  
Cultured Hepatocytes ◽  
Rat Liver Cells

Rat hepatocytes cultured from 24h lose 60% of their NAD content. By using the differential response to inhibitors of the two major enzymes that catabolize NAD in mammalian cells, it is shown that poly(ADP-ribose) polymerase is responsible for the loss of NAD. The relevance of this observation to the use of cultured hepatocytes for the study of DNA repair induced by carcinogens is discussed.

scholarly journals A METHOD FOR THE QUANTITATIVE ESTIMATION OF CYTOPLASMIC STRUCTURES

1962 ◽  
Vol 15 (3) ◽  
pp. 481-487 ◽  
Author(s):  
Alden V. Loud
Keyword(s):  
Endoplasmic Reticulum ◽  
Rat Liver ◽  
Electron Micrographs ◽  
Quantitative Estimation ◽  
Liver Cells ◽  
Sampling Procedure ◽  
Rat Liver Cells ◽  
Normal Rat ◽  
Cytoplasmic Structures

A sampling procedure and calculations are described by which electron micrographs of cytoplasmic structures may be quantitatively analyzed. The relative areas occupied by formed bodies and by the "membrane space," the remainder of the cytoplasm, are evaluated. A method for making a measurement of the quantity of endoplasmic reticulum or other membrane profiles is described. The technic and results are illustrated with normal rat liver cells.

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