scholarly journals CYTOMORPHOMETRY OF DEVELOPING RAT LIVER AND ITS APPLICATION TO ENZYMIC DIFFERENTIATION

1972 ◽  
Vol 52 (2) ◽  
pp. 261-272 ◽  
Author(s):  
Olga Greengard ◽  
Micheline Federman ◽  
W. Eugene Knox
Keyword(s):  
Rat Liver ◽  
Kupffer Cells ◽  
Unit Volume ◽  
Fetal Liver ◽  
Parenchymal Cell ◽  
Liver Volume ◽  
Adult Life ◽  
Hematopoietic Tissue ◽  
The Mean ◽  
Parenchymal Cells

Quantitative stereological methods have been adapted for the measurement of the volume of liver attributable to parenchymal, hematopoietic, and Kupffer cells and for the measurement of the relative and absolute number (per unit volume) of these cell types and the mean volume of the parenchymal cell. These morphological parameters are the main ones for interpreting the biochemical differentiation of liver. Quantitative changes in these parameters, in rat liver between the 15th day of gestation and adult life, are presented. Despite the large number of hematopoietic cells, the parenchymal cells fill more than half of the liver volume between the 15th and 18th days of gestation and 0.85 of the liver volume at term. The fraction of liver volume occupied by Kupffer cells is never more than 0.02; the number of Kupffer cells per cubic centimeter increases less than twofold between fetal and adult life. The mean volume of individual parenchymal cells undergoes a threefold rise during late fetal life, declines in the neonatal period, and doubles between the 12th and 28th postnatal days. With the morphometric data obtained, it is impossible to convert enzyme concentrations (units per gram, determined in homogenates of whole liver) to enzyme amounts per unit volume of parenchymal or hematopoietic tissue or per individual cell of either type. In late fetal liver, only rises in enzyme concentration less than twofold may be attributed to the enrichment of parenchymal tissue at the expense of hematopoietic elements. The sudden upsurge, by more than twofold, of hepatic enzymes of the late fetal cluster (and also of the neonatal and late suckling cluster) reflects rises per parenchymal mass and per parenchymal cell. Thyroxine and glucagon, the administration of which to fetal rats promotes enzyme differentiation in liver, are without appreciable effect on the cytological parameters studied. Hydrocortisone accelerates the involution of hematopoietic tissue in fetal liver. Enzymes that are diminished by prenatal injection of hydrocortisone may be concentrated in hematopoietic cells.

scholarly journals Hepatic lipase is localized at the parenchymal cell microvilli in rat liver

1997 ◽  
Vol 321 (2) ◽  
pp. 425-430 ◽  
Author(s):  
Belinda BREEDVELD ◽  
Kees SCHOONDERWOERD ◽  
Adrie J. M. VERHOEVEN ◽  
Rob WILLEMSEN ◽  
Hans JANSEN
Keyword(s):  
Endothelial Cells ◽  
Rat Liver ◽  
Kupffer Cells ◽  
Binding Capacity ◽  
Hepatic Lipase ◽  
Parenchymal Cell ◽  
Liver Cells ◽  
Minor Amount ◽  
Parenchymal Liver ◽  
Parenchymal Cells

Hepatic lipase (HL) is thought to be located at the vascular endothelium in the liver. However, it has also been implicated in the binding and internalization of chylomicron remnants in the parenchymal cells. In view of this apparent discrepancy between localization and function, we re-investigated the localization of HL in rat liver using biochemical and immunohistochemical techniques. The binding of HL to endothelial cells was studied in primary cultures of rat liver endothelial cells. Endothelial cells bound HL in a saturable manner with high affinity. However, the binding capacity accounted for at most 1% of the total HL activity present in the whole liver. These results contrasted with earlier studies, in which non-parenchymal cell (NPC) preparations had been found to bind HL with a high capacity. To study HL binding to the different components of the NPC preparations, we separated endothelial cells, Kupffer cells and blebs by counterflow elutriation. Kupffer cells and endothelial cells showed a relatively low HL-binding capacity. In contrast, the blebs, representing parenchymal-cell-derived material, had a high HL-binding capacity (33 m-units/mg of protein) and accounted for more than 80% of the total HL binding in the NPC preparation. In contrast with endothelial and Kupffer cells, the HL-binding capacity of parenchymal cells could account for almost all the HL activity found in the whole liver. These data strongly suggest that HL binding occurs at parenchymal liver cells. To confirm this conclusion in situ, we studied HL localization by immunocytochemical techniques. Using immunofluorescence, we confirmed the sinusoidal localization of HL. Immunoelectron microscopy demonstrated that virtually all HL was located at the microvilli of parenchymal liver cells, with a minor amount at the endothelium. We conclude that, in rat liver, HL is localized at the microvilli of parenchymal cells.

l-Thyroxine enters the rat liver cell by simple diffusion

1983 ◽  
Vol 97 (2) ◽  
pp. 277-282 ◽  
Author(s):  
G. S. Rao ◽  
M. L. Rao
Keyword(s):  
Rat Liver ◽  
Arrhenius Plot ◽  
Parenchymal Cell ◽  
Liver Cells ◽  
Liver Parenchymal Cell ◽  
Simple Diffusion ◽  
Liver Parenchymal ◽  
Isolated Rat Liver ◽  
Centrifugation Technique ◽  
Parenchymal Cells

The mode of uptake of l-[125I]thyroxine by freshly isolated rat liver parenchymal cells was studied by a rapid centrifugation technique. Using conditions for measuring initial rates of uptake, uptake by liver cells was not saturable when exposed to hormone concentrations in the incubation medium ranging from 2 pmol/l to 10 μmol/l. The Arrhenius plot was linear from 2 to 37°C; the temperature coefficient was 1·4. The uptake of l-[125I]thyroxine by liver cells was 35% when compared with that of l-[125I]tri-iodothyronine. In the presence of 2·8% bovine serum albumin the rate of uptake of l-[125I]thyroxine by liver cells was reduced by 90%. These results suggest that l-[125I]thyroxine enters the rat liver parenchymal cell by simple diffusion and only the free hormone crosses the plasma membrane.

scholarly journals The uptake and metabolism of chylomicron-remnant lipids by rat liver parenchymal and non-parenchymal cells in vitro

1985 ◽  
Vol 232 (2) ◽  
pp. 395-401 ◽  
Author(s):  
P M Lippiello ◽  
P J Sisson ◽  
M Waite
Keyword(s):  
Endothelial Cells ◽  
Rat Liver ◽  
Kupffer Cells ◽  
Liver Cell ◽  
Cholesterol Ester ◽  
Cell Types ◽  
Chylomicron Remnant ◽  
Parenchymal Cells ◽  
Uptake And Metabolism

The uptake and metabolism of chylomicron-remnant lipids by individual liver cell types was examined by incubating remnants with monolayer cultures of hepatocytes, Kupffer cells, and endothelial cells from rat liver. Remnants were prepared in vitro from radiolabelled mesenteric-lymph chylomicra, utilizing either purified lipoprotein lipase from bovine milk, or plasma isolated from heparinized rats. The resulting particles contained [3H]phosphatidylcholine and cholesterol, and [14C]oleate in the acylglycerol, phospholipid, fatty-acid and cholesterol-ester fractions. The capacities of the three cell types for uptake of both [3H]lipids and [14C]lipids were determined to be, on a per-cell basis, in the order: Kupffer greater than hepatocytes greater than endothelial. The relative proportions of [3H]phospholipid and total [3H]cholesterol taken up by hepatocytes and non-parenchymal cells remained constant with time. The uptake of [14C]oleoyl lipids by all three cell types was slightly greater than that of the total [3H]cholesterol and [3H]phospholipid components. There was evidence of cholesterol-ester hydrolysis and turnover of [14C]oleate in the phospholipid fraction in hepatocytes and Kupffer cells, but not endothelial cells, over the first 2 h. With both remnant preparations, these observations indicate that significant differences exist between the three major liver cell types with respect to the uptake and metabolism of remnant lipid components.

Stimulation of oxygen uptake by prostaglandin E2 is oxygen dependent in perfused rat liver

1998 ◽  
Vol 275 (3) ◽  
pp. G542-G549 ◽  
Author(s):  
Wei Qu ◽  
Zhi Zhong ◽  
Gavin E. Arteel ◽  
Ronald G. Thurman
Keyword(s):  
Oxygen Uptake ◽  
Oxygen Tension ◽  
Rat Liver ◽  
Kupffer Cells ◽  
High Flow ◽  
Perfused Rat Liver ◽  
Normal Flow ◽  
Flow Rates ◽  
Glucose Output ◽  
Parenchymal Cells

The aim of this study was to determine if the effect of prostaglandin E2(PGE2) on hepatic oxygen uptake was affected by oxygen tension. Livers from fed female Sprague-Dawley rats were perfused at normal or high flow rates (4 or 8 ml ⋅ g−1 ⋅ min−1) to vary local oxygen tension within the liver lobule. During perfusion at normal flow rates, PGE2 (5 μM) infusion increased oxygen uptake by about 50 μmol ⋅ g−1 ⋅ h−1; however, when livers were perfused at high flow rates, the increase was nearly twice as large. Simultaneously, glucose output was increased rapidly by about 50%, whereas glycolysis was decreased about 60%. When flow rate was held constant, increases in oxygen uptake due to PGE2 were proportional to oxygen delivery. Infusion of PGE2 into livers perfused at normal flow rates increased state 3 rates of oxygen uptake of subsequently isolated mitochondria by about 25%; however, rates were increased 50–75% in mitochondria isolated from livers perfused at high flow rates. Thus it is concluded that PGE2stimulates oxygen uptake via mechanisms regulated by oxygen tension in perfused rat liver. High flow rates also increased basal rates of oxygen uptake: this increase was prevented by inactivation of Kupffer cells with GdCl3. In addition, conditioned medium from Kupffer cells incubated at high oxygen tension (75% oxygen) stimulated oxygen uptake of isolated parenchymal cells by >30% and elevated PGE2production about twofold compared with Kupffer cells exposed to normal air-saturated buffer (21% oxygen). These effects were blocked completely by both indomethacin and nisoldipine. These data support the hypothesis that oxygen stimulates Kupffer cells to release mediators such as PGE2 which elevate oxygen consumption in parenchymal cells, possibly by mechanisms involving cyclooxygenase and calcium channels.

Release of osmolytes induced by phagocytosis and hormones in rat liver

2000 ◽  
Vol 278 (2) ◽  
pp. G227-G233 ◽  
Author(s):  
Matthias Wettstein ◽  
Thorsten Peters-Regehr ◽  
Ralf Kubitz ◽  
Richard Fischer ◽  
Claudia Holneicher ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cell Volume ◽  
Rat Liver ◽  
Kupffer Cells ◽  
Hepatic Stellate Cells ◽  
Stellate Cells ◽  
Receptor Expression ◽  
Sinusoidal Endothelial Cells ◽  
Fluorescence Measurements ◽  
Parenchymal Cells

Betaine, taurine, and inositol participate as osmolytes in liver cell volume homeostasis and interfere with cell function. In this study we investigated whether osmolytes are also released from the intact liver independent of osmolarity changes. In the perfused rat liver, phagocytosis of carbon particles led to a four- to fivefold stimulation of taurine efflux into the effluent perfusate above basal release rates. This taurine release was inhibited by 70–80% by the anion exchange inhibitor DIDS or by pretreatment of the rats with gadolinium chloride. Administration of vasopressin, cAMP, extracellular ATP, and glucagon also increased release of betaine and/or taurine, whereas insulin, extracellular UTP, and adenosine were without effect. In isolated liver cells, it was shown that parenchymal cells and sinusoidal endothelial cells, but not Kupffer cells and hepatic stellate cells, release osmolytes upon hormone stimulation. This may be caused by a lack of hormone receptor expression in these cells, because single-cell fluorescence measurements revealed an increase of intracellular calcium concentration in response to vasopressin and glucagon in parenchymal cells and sinusoidal endothelial cells but not in Kupffer cells and hepatic stellate cells. The data show that Kupffer cells release osmolytes during phagocytosis via DIDS-sensitive anion channels. This mechanism may be used to compensate for the increase in cell volume induced by the ingestion of phagocytosable material. The physiological significance of hormone-induced osmolyte release remains to be evaluated.

scholarly journals LIVER PARENCHYMAL CELL INJURY

1965 ◽  
Vol 25 (3) ◽  
pp. 53-75 ◽  
Author(s):  
Edward S. Reynolds
Keyword(s):  
Rat Liver ◽  
Inorganic Phosphate ◽  
Cell Injury ◽  
Parenchymal Cell ◽  
Mitochondrial Atpase ◽  
Liver Parenchymal Cell ◽  
Liver Parenchymal ◽  
Serum Inorganic Phosphate ◽  
Chemical Events ◽  
Parenchymal Cells

Accumulation of calcium in the mitochondria of rat liver parenchymal cells at 16 and 24 hours after poisoning with carbon tetrachloride is associated with an increase in amount of liver inorganic phosphate, the persistence of mitochondrial adenosine triphosphatase activity, and the formation of electron-opaque intramitochondrial masses in cells with increased calcium contents. These masses, which form within the mitochondrial matrix adjacent to internal mitochondrial membranes, resemble those observed in isolated mitochondria which accumulate calcium and inorganic phosphate; are present in a locus similar to that of electron opacities which result from electron-histochemical determination of mitochondrial ATPase activity; and differ in both appearance and position from matrix granules of normal mitochondria. After poisoning, normal matrix granules disappear from mitochondria prior to their accumulation of calcium. As calcium-associated electron-opaque intramitochondrial masses increase in size, mitochondria degenerate in appearance. At the same time, cytoplasmic membrane systems of mid-zonal and centrilobular cells are disrupted by degranulation of the rough endoplasmic reticulum and the formation of labyrinthine tubular aggregates. The increase in amount of inorganic phosphate in rat liver following poisoning is balanced by a decreased amount of phosphoprotein. These chemical events do not appear to be related, however, as the inorganic phosphate accumulated is derived from serum inorganic phosphate.

Cellular distribution of somatogenic receptors and insulin-like growth factor-I mRNA in the rat liver

1988 ◽  
Vol 119 (1) ◽  
pp. 69-NP ◽  
Author(s):  
L. van Neste ◽  
B. Husman ◽  
C. Möller ◽  
G. Andersson ◽  
G. Norstedt
Keyword(s):  
Growth Factor ◽  
Rat Liver ◽  
Parenchymal Cell ◽  
Cell Fraction ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I ◽  
Cell Fractions ◽  
Parenchymal Cells

ABSTRACT Parenchymal and non-parenchymal cell fractions isolated from rat liver were analysed for the distribution of somatogenic receptors and for insulin-like growth factor-I (IGF-I) mRNA. The effect of hypophysectomy either alone or in combination with a single injection of human GH (hGH) on the levels of IGF-I mRNA was also studied in the two cell fractions. The contamination of parenchymal cells in the non-parenchymal cell fraction was in the range of 2– 3%. Somatogenic receptors were found only in the parenchymal cell fraction. IGF-I mRNA was detected in both cell fractions, although the level of this mRNA was about fivefold higher in parenchymal cells. When RNA was studied by Northern gel analysis no major differences were observed in the size distribution of IGF-I transcripts in the two cell fractions. In hypophysectomized animals, the IGF-I mRNA level was decreased to 10 and 30% of control values in the parenchymal and non-parenchymal cell fractions respectively. Treatment of hypophysectomized animals with a single dose of hGH restored IGF-I mRNA in parenchymal and in non-parenchymal cells to the extent found in intact animals. In conclusion, our data indicate that somatogenic receptors are exclusively, and IGF-I mRNA predominantly, expressed in liver parenchymal cells compared with a total non-parenchymal cell fraction. The most marked effect of GH, correlating with the presence of somatogenic receptors, was seen in the parenchymal cells. The minor non-GH dependent expression of IGF-I mRNA suggests that this peptide may elicit effects in addition to the well-established GH-dependent activity. J. Endocr. (1988) 119, 69–74

scholarly journals Liver endothelium and not hepatocytes or Kupffer cells have transferrin receptors

Blood ◽  
1984 ◽  
Vol 63 (2) ◽  
pp. 270-276
Author(s):  
R Soda ◽  
M Tavassoli
Keyword(s):  
Endothelial Cells ◽  
Rat Liver ◽  
Kupffer Cells ◽  
Liver Cell ◽  
Cell Suspensions ◽  
Transferrin Receptors ◽  
Visual Probe ◽  
Covalently Linked ◽  
Parenchymal Cells

Using a visual probe, consisting of latex minibeads covalently linked to transferrin (TF), we found that, in rat liver cell suspensions, transferrin receptors were limited to endothelial cells. Neither hepatocytes nor Kupffer cells contained an appreciable number of TF receptors. Specificity of this reaction was demonstrated by preincubation with non-derivatized TF, which inhibited the binding. This was further confirmed by fractionation of liver cell suspensions on metrizamide gradients. The uptake of either the visual probe or 125I- labeled TF was again limited to the endothelium-rich fraction. Transferrin bound to endothelial membrane was internalized at 37 degrees C, but not at 4 degrees C, via a coated pit system. Again, hepatocytes and Kupffer cells did not internalize the probe. The findings suggest that iron may be first taken up by liver endothelium and then transmitted to parenchymal cells. These results emphasize the generally unappreciated role of endothelium in the transport across the tissue-blood barrier.

scholarly journals Liver endothelium and not hepatocytes or Kupffer cells have transferrin receptors

Blood ◽  
1984 ◽  
Vol 63 (2) ◽  
pp. 270-276 ◽  
Author(s):  
R Soda ◽  
M Tavassoli
Keyword(s):  
Endothelial Cells ◽  
Rat Liver ◽  
Kupffer Cells ◽  
Liver Cell ◽  
Cell Suspensions ◽  
Transferrin Receptors ◽  
Visual Probe ◽  
Covalently Linked ◽  
Parenchymal Cells

Abstract Using a visual probe, consisting of latex minibeads covalently linked to transferrin (TF), we found that, in rat liver cell suspensions, transferrin receptors were limited to endothelial cells. Neither hepatocytes nor Kupffer cells contained an appreciable number of TF receptors. Specificity of this reaction was demonstrated by preincubation with non-derivatized TF, which inhibited the binding. This was further confirmed by fractionation of liver cell suspensions on metrizamide gradients. The uptake of either the visual probe or 125I- labeled TF was again limited to the endothelium-rich fraction. Transferrin bound to endothelial membrane was internalized at 37 degrees C, but not at 4 degrees C, via a coated pit system. Again, hepatocytes and Kupffer cells did not internalize the probe. The findings suggest that iron may be first taken up by liver endothelium and then transmitted to parenchymal cells. These results emphasize the generally unappreciated role of endothelium in the transport across the tissue-blood barrier.

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