scholarly journals Comparison of cadmium-metallothionein synthesis in parenchymal and non-parenchymal rat liver cells

1983 ◽  
Vol 210 (3) ◽  
pp. 769-773 ◽  
Author(s):  
K Cain ◽  
D N Skilleter
Keyword(s):  
Rat Liver ◽  
Cell Separation ◽  
Metal Uptake ◽  
Time Course ◽  
Cell Types ◽  
Separation Technique ◽  
Limiting Factor ◽  
Rat Liver Cells ◽  
A Cell ◽  
Parenchymal Cells

The time course of cadmium-metallothionein synthesis was studied in non-parenchymal and parenchymal cells, isolated by a cell-separation technique from the livers of rats after the simultaneous injection of CdCl2 (0.05 mg of Cd/kg) and a 10-fold molar excess of 2,3-dimercaptopropanol. Under these conditions of dosing, in contrast with the injection of CdCl2 alone, both cell types accumulate similar concentrations of Cd and synthesize equivalent concentrations of metallothionein. It is concluded that both cell types have a similar capacity to synthesize the metalloprotein, and that the limiting factor under normal cadmium exposure is the relatively inefficient metal uptake into the non-parenchymal cells.

Evidence for the presence of a cell-surface ribonuclease in mechanically prepared rat-liver cells in suspension

1982 ◽  
Vol 2 (10) ◽  
pp. 751-760 ◽  
Author(s):  
R. Sirdeshmukh ◽  
P. M. Bhargava
Keyword(s):  
Escherichia Coli ◽  
Cell Surface ◽  
Rat Liver ◽  
Degradation Products ◽  
Sucrose Density Gradient ◽  
Liver Parenchymal ◽  
Rat Liver Cells ◽  
A Cell ◽  
Parenchymal Cells ◽  
Soluble Material

Rat-liver parenchymal cells obtained in suspension by a mecahnical method are shown to contain a cell-surface nuclease(s) that rapidly degrades exogenously added total Escherichia coli RNA. However, no acid-soluble products are formed; all the degradation products in the incubation medium sediment in the 4–55 RNA region on a sucrose density gradient. A part of the degraded RNA seems to be taken up by the cells; the uptake of the degradation products, presumably derived from rRNAs, is more than that of purified 4–55 RNA. Most of the RNA taken up by the cell sediments in the 4–55 region; only a small proportion is degraded to acid-soluble material within the cell.

scholarly journals Characterization of retroendocytosis in rat liver parenchymal cells and sinusoidal endothelial cells

1992 ◽  
Vol 287 (1) ◽  
pp. 241-246 ◽  
Author(s):  
S Magnusson ◽  
I Faerevik ◽  
T Berg
Keyword(s):  
Endothelial Cells ◽  
Cell Surface ◽  
Rat Liver ◽  
Early Stage ◽  
Cell Types ◽  
Endocytic Pathway ◽  
Sinusoidal Endothelial Cells ◽  
Rat Liver Cells ◽  
Major Factors ◽  
Parenchymal Cells

After receptor-mediated endocytosis, internalized ligands may be recycled to the cell surface instead of being routed to lysosomes for degradation, a process termed retroendocytosis. We have investigated the kinetics and extent of retroendocytosis of neoglycoproteins after internalization via two carbohydrate-specific receptors in rat liver cells: galactose receptors in parenchymal cells (PC) and mannose receptors in sinusoidal endothelial cells (EC). Retroendocytosis in both cell types occurred with first-order kinetics, and the rate of recycling of internalized ligands was about 4 times higher in EC than in PC. As the length of the internalization pulse was increased, the extent of subsequent retroendocytosis decreased, indicating that retroendocytosis takes place from a relatively early stage in the endocytic pathway. Furthermore, as the degree of carbohydrate substitution of the neoglycoprotein ligands increased, the affinities of the receptors for the ligands and the extent of ligand retroendocytosis increased. In the EC, the relationship between degree of substitution and extent of retroendocytosis was not immediately apparent, as some of the neoglycoprotein ligands used may also bind to and be internalized by scavenger receptors on the EC, causing a decreased apparent retroendocytosis. However, when this interaction was inhibited, this relationship was restored. We conclude that retroendocytosis mainly occurs because of incomplete dissociation of ligands from receptors before receptor recycling to the cell surface and that the affinities of a receptor for its ligand at the cell surface and in the endosomal environment are major factors in determining the extent of retroendocytosis.

scholarly journals Selective uptake of cadmium by the parenchyumal cells of liver

1980 ◽  
Vol 188 (1) ◽  
pp. 285-288 ◽  
Author(s):  
K Cain ◽  
D N Skilleter
Keyword(s):  
Cell Separation ◽  
Separation Technique ◽  
Cadmium Uptake ◽  
Selective Uptake ◽  
Sinusoidal Cells ◽  
Liver Parenchymal ◽  
A Cell ◽  
Parenchymal Cells ◽  
Uptake And Metabolism

The uptake of cadmium in vivo into parenchymal and non-parenchymal (sinusoidal) cells of the liver was studied by a cell-separation technique. Liver parenchymal cells accumulate cadmium more readily than do non-parenchymal cells and synthesize metallothionein. It is proposed that cadmium uptake and metabolism from injected CdCl2, is restricted almost exclusively to the liver parenchymal cells.

scholarly journals The distribution, induction and isoenzyme profile of glutathione S-transferase and glutathione peroxidase in isolated rat liver parenchymal, Kupffer and endothelial cells

1989 ◽  
Vol 264 (3) ◽  
pp. 737-744 ◽  
Author(s):  
P Steinberg ◽  
H Schramm ◽  
L Schladt ◽  
L W Robertson ◽  
H Thomas ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Glutathione Peroxidase ◽  
Rat Liver ◽  
Peroxidase Activity ◽  
Cell Types ◽  
Transferase Activity ◽  
Glutathione Peroxidase Activity ◽  
Glutathione S Transferase ◽  
Liver Parenchymal ◽  
Parenchymal Cells

The distribution and inducibility of cytosolic glutathione S-transferase (EC 2.5.1.18) and glutathione peroxidase (EC 1.11.1.19) activities in rat liver parenchymal, Kupffer and endothelial cells were studied. In untreated rats glutathione S-transferase activity with 1-chloro-2,4-dinitrobenzene and 4-hydroxynon-2-trans-enal as substrates was 1.7-2.2-fold higher in parenchymal cells than in Kupffer and endothelial cells, whereas total, selenium-dependent and non-selenium-dependent glutathione peroxidase activities were similar in all three cell types. Glutathione S-transferase isoenzymes in parenchymal and non-parenchymal cells isolated from untreated rats were separated by chromatofocusing in an f.p.l.c. system: all glutathione S-transferase isoenzymes observed in the sinusoidal lining cells were also detected in the parenchymal cells, whereas Kupffer and endothelial cells lacked several glutathione S-transferase isoenzymes present in parenchymal cells. At 5 days after administration of Arocolor 1254 glutathione S-transferase activity was only enhanced in parenchymal cells; furthermore, selenium-dependent glutathione peroxidase activity decreased in parenchymal and non-parenchymal cells. At 13 days after a single injection of Aroclor 1254 a strong induction of glutathione S-transferase had taken place in all three cell types, whereas selenium-dependent glutathione peroxidase activity remained unchanged (endothelial cells) or was depressed (parenchymal and Kupffer cells). Hence these results clearly establish that glutathione S-transferase and glutathione peroxidase are differentially regulated in rat liver parenchymal as well as non-parenchymal cells. The presence of glutathione peroxidase and several glutathione S-transferase isoenzymes capable of detoxifying a variety of compounds in Kupffer and endothelial cells might be crucial to protect the liver from damage by potentially hepatotoxic substances.

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.

Tissue Plasminogen Activator is Endocytosed by Mannose and Galactose Receptors of Rat Liver Cells

1988 ◽  
Vol 59 (03) ◽  
pp. 480-484 ◽  
Author(s):  
Bård Smedsrød ◽  
Monica Einarsson ◽  
Håkan Pertoft
Keyword(s):  
Endothelial Cells ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Rat Liver ◽  
Side Chains ◽  
Diisopropyl Fluorophosphate ◽  
Tissue Plasminogen ◽  
Rat Liver Cells ◽  
Liver Endothelial Cells ◽  
Parenchymal Cells

SummaryExperiments were carried out to charact erize the specificity of uptake of tPA in rat liver cells. Endocytosis in liver endothelial cells of the native carbohydrate variants of tissue plasminogen activator (tPA), and tPA inactivated by diisopropyl fluorophosphate was found to be competitive, suggesting that the determinant being recognized by these cells is different from the active site. Fibronectin and urokinase, which show partial homology with tPA, did not compete with tPA for uptake in liver endothelial cells. Hyaluronic acid, collagen, or IgG, which are endocytosed by specific receptors in liver endothelial cells, did not interfere with the uptake.Reduced endocytosis by liver endothelial cells was observed with tPA modified in the carbohydrate side chains, suggesting that these structures are important for uptake. Ovalbumin, mannan, mannose, fructose, and EDTA, but not galactose, effectively inhibited uptake in liver endothelial cells of both native and diisopropyl fluorophosphate-inhibited tPA, but had very little effect on the uptake of tPA modified in the carbohydrate side chains.Endocytosis of native tPA by parenchymal cells could be inhibited by galactose, ovalbumin, and EDTA, but not by mannose.These results suggest that endocytosis of tPA by liver endothelial cells and parenchymal cells is mediated by the mannose and galactose receptors, respectively.

scholarly journals The variation with age of the structure of chromatin in three cell types from rat liver

1979 ◽  
Vol 179 (2) ◽  
pp. 291-298 ◽  
Author(s):  
V Zongza ◽  
A P Mathias
Keyword(s):  
Rat Liver ◽  
Cell Types ◽  
Repeat Length ◽  
Micrococcal Nuclease ◽  
Dna Repeat ◽  
Old Rats ◽  
Parenchymal Cells ◽  
Kinetics Of

The organization of chromatin in three rat liver nuclear populations, namely diploid stromal, diploid parenchymal, and tetraploid parenchymal nuclei, which were separated by zonal centrifugation, was studied by digestion with micrococcal nuclease and pancreatic deoxyribonuclease in 3-week-old rats in which the parenchymal cells contain diploid nuclei and in 2-and 4-month-old rats with a high proportion of tetraploid nuclei. Digestion by micrococcal nuclease allowed the estimation of DNA-repeat length in chromatin. Parenchymal nuclei have shorter repeat length than stromal nuclei and DNA-repeat length increases with the age in all three nuclei populations. The kinetics of digestion by micrococcal nuclease showed that nuclei with shorter repeat length are more sensitive to micrococcal nuclease and that the sensitivity of chromatin decreases with age for all the types of nuclei in this study. The kinetics of digestion by pancreatic deoxyribonuclease showed that sensitivity of chromatin is related to the repeat length and that the sensitivity decreases with the ages.

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 Immunocytochemical studies on the localization of plasma and of cellular retinol-binding proteins and of transthyretin (prealbumin) in rat liver and kidney.

1984 ◽  
Vol 98 (5) ◽  
pp. 1696-1704 ◽  
Author(s):  
M Kato ◽  
K Kato ◽  
D S Goodman
Keyword(s):  
Rat Liver ◽  
Binding Protein ◽  
Cell Types ◽  
Retinol Binding Protein ◽  
Specific Staining ◽  
Intense Staining ◽  
Cytoplasmic Staining ◽  
Liver And Kidney ◽  
Diffuse Cytoplasmic Staining ◽  
Parenchymal Cells

The immunocytochemical localization of cellular retinol-binding protein (CRBP), of plasma retinol-binding protein (RBP), and of plasma transthyretin (TTR) was studied in rat liver and kidney. The studies employed normal rats, retinol-deficient rats, and rats fed excess retinol. Antisera were prepared in rabbits against purified rat CRBP, RBP, and TTR. The primary antibodies and goat anti-rabbit IgG were purified by immunosorbent affinity chromatography, using the respective pure antigen coupled to Sepharose as the immunosorbent. This procedure effectively removed cross-reactive and heterophile antibodies, which permitted the specific staining and localization of each antigen by the unlabeled peroxidase-antiperoxidase method. CRBP was found to be localized in two cell types in the liver, the parenchymal cells and the fat-storing cells. Diffuse cytoplasmic staining for CRBP was seen in all the parenchymal cells. Much more intense staining for CRBP was seen in the fat-storing cells. The prominence of the CRBP-positive fat-storing cells changed markedly with vitamin A status. Thus, these cells were most prominent, and appeared most numerous, in liver from rats fed excess retinol. Both RBP and TTR were localized within liver parenchymal cells. The intensity of RBP staining increased markedly in retinol-deficient rat liver, consistent with previous biochemical observations. With the methods employed, specific staining for RBP or TTR was not seen in cells other than the parenchymal cells. In the kidney, all three proteins (CRBP, RBP, and TTR) were localized in the proximal convoluted tubules of the renal cortex. Staining for RBP was much more intense in normal kidney than in kidney from retinol-deficient rats. These findings reflect the fact that RBP in the tubules represents filtered and reabsorbed RBP. The pattern of specific staining for CRBP among the various tubules was very similar to that seen for RBP on adjacent, serial sections of kidney. The function of CRBP in the kidney is not known.

scholarly journals Hemoglobin and Erythrocyte Catabolism in Rat Liver: The Separate Roles of Parenchymal and Sinusoidal Cells

Blood ◽  
1972 ◽  
Vol 40 (6) ◽  
pp. 812-822 ◽  
Author(s):  
D. Montgomery Bissell ◽  
Lydia Hammaker ◽  
Rudi Schmid
Keyword(s):  
Rat Liver ◽  
Cell Types ◽  
Hepatic Cell ◽  
Sinusoidal Cells ◽  
Plasma Hemoglobin ◽  
Sinusoidal Cell ◽  
Hemoglobin Molecule ◽  
Cell Fractions ◽  
Parenchymal Cells ◽  
Stimulation Of

Abstract The liver participates in the removal from the circulation of both damaged red blood cells (RBC) and plasma hemoglobin. The specific hepatic cell types involved in these processes have been identified by fractionation of rat liver into pure isolates of parenchymal and sinusoidal cells. After injection of 59Fe-labeled hemoglobin, 85%-95% of the radioactivity in the liver was associated with the parenchymal cells, regardless of whether the hemoglobin was bound to haptoglobin or was free in plasma. By contrast, 59Fe-labeled spherocytic RBC were sequestered entirely by the sinusoidal cell population. Stimulation of microsomal heme oxygenase by administered hemoglobin or RBC indicated that these cell fractions not only sequester but also degrade the ingested hemoglobin-heme. Infusion of doubly labeled 59Fe, 125-I-hemoglobin indicated that the hepatic parenchymal cells remove the intact hemoglobin molecule without exchange or transfer of the heme moiety to other carrier proteins. By contrast, heme bound to albumin was detached from the albumin before its uptake by the parenchymal cells. These findings suggest that, contrary to previous belief, hepatic parenchymal cells play a key role in the metabolism of plasma hemoglobin.

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