In vivo binding and uptake of low-density lipoprotein-gold- and albumin-gold conjugates by parenchymal and sinusoidal cells of the fetal rat liver

Franke, H; Dürer, U; Schlag, B; Dargel, R.

doi:10.1007/bf00215437

Cited by 9 publications

(9 citation statements)

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“…Thus, in sepa rate experiments it could be shown that estro gen significantly decreased the serum LDL apoB concentration from day 30 after birth. The presence of estrogen receptors in fetal 233 rodents has been repeatedly documented [24][25][26], In connection with our own studies it seems to be of interest that the transcription mechanism responds to estrogen in various tissues also during fetal development [26], In a morphological study with gold-labeled LDL Franke et al [3] found a stimulation of LDL uptake into the fetal liver by estrogen. In in vivo experiments the uptake of gold-labeled LDL into either liver parenchymal cells or Kupffer's cells was increased 2-fold.…”

Section: Discussionmentioning

confidence: 90%

“…In summary, the LDL catabolism of the rat is insensitive towards estrogen in the late gestational period and during the first 2 weeks of postnatal life [3], The efflux of the atherogenic LDL from the blood stream is mainly mediated via spe cific receptors. Elimination occurs for the ma jor part in the liver, which is a key organ in the regulation of the plasma LDL concentration in certain species including man [1], The he patic LDL receptor was found to be expressed in rats [2][3][4], cattle [5], pigs [6] and humans [7] also in the fetal state, and a high negative correlation was found between the fetal plasma cholesterol and the LDL receptor con centration [5][6][7]. The expression of the heDr.…”

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confidence: 99%

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Low-Density Lipoprotein Catabolism does not Respond to Estrogen in the Fetal and Newborn Rat

Plonné

Winkler²,

Schröter³

et al. 1993

Neonatology

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The elimination of native and methylated low-density lipoprotein (LDL) from serum and the effect of estradiol on the serum LDL-apoB pool, the uptake of homologous [¹²⁵I]-LDL into liver and adrenals, and the fractional catabolic rate (FCR) of [¹²⁵I]-LDL was studied in fetal (22nd day of gestation), newborn (15th day postpartum), and adult rats. In fetal rats the receptor-mediated LDL decay accounted only for 47%, whereas in adults it was calculated to 65%. In the latter, estrogen caused (1) a diminution of the serum LDL-apoB pool by 85%; (2) an enhancement of the LDL uptake into the liver and the adrenals by 5- and 10-fold, respectively, and (3) an acceleration of the [¹²⁵I]-LDL decay in the serum with a rise of the FCR by 3-fold. In contrast, neither the LDL pool and uptake nor the LDL elimination (FCR) did respond to estrogen in fetal and newborn rats. In summary, the LDL catabolism of the rat is insensitive towards estrogen in the late gestational period and during the first 2 weeks of postnatal life [3].

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Section: Discussionmentioning

confidence: 90%

mentioning

confidence: 99%

Low-Density Lipoprotein Catabolism does not Respond to Estrogen in the Fetal and Newborn Rat

Plonné

Winkler²,

Schröter³

et al. 1993

Neonatology

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“…Albumin enters the cell via a caveolae-dependent endocytosis pathway (Franke et al, 1987;Schubert et al, 2001). R-MT was mixed with F-albumin, and the uptake of the protein mixture was imaged in a single cell (Fig.…”

Section: Cellular Uptake Of Mt By Endocytosismentioning

confidence: 99%

Lipid raft‐dependent endocytosis of metallothionein in HepG2 cells

Hao

Hong

Maret

2006

Journal Cellular Physiology

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Human hepatocellular carcinoma (HepG2) cells take up metallothionein (MT) by endocytosis. MT co-localizes with albumin but not with transferrin, indicating uptake via a non-classical pathway rather than via clathrin-mediated endocytosis. A lipid raft-dependent uptake is indicated by pravastatin inhibition of cholesterol synthesis and methyl-beta-cyclodextrin inhibition of cholesterol translocation to the plasma membrane, reducing MT uptake by 29% and 69%, respectively. Subcellular fractionation after MT uptake reveals significant amounts of MT in vesicular fractions including lysosomes but virtually no MT in the cytosol. Metals bound to MT are released into the cytosol, however. The findings define a pathway for cellular metal acquisition. Together with results from other studies demonstrating secretion of MT from different cells and the presence of MT in extracellular fluids, the results suggest a function of MT in intercellular communication.

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“…Colloidal gold particles of different sizes can be easily produced (24,50,54) and macromolecules such as enzymes, antibodies, lipoproteins, and hormones can be directly adsorbed on their surfaces (10,15,22,28) without modification of their biochemical and physiological properties (18,42,44,47,49,55). The one known exception 387 388 CATHIENI, TABAN is catalase (27).…”

Section: -401 1992)mentioning

confidence: 99%

“…With immunostaining techniques, visualization of the binding site-antibody complex is presently carried out by using a second FITC-or RITC-labeled antibody or with the use of peroxidase, ferritin or, more recently, colloidal gold (5,17,45,50,63). When used, colloidal gold particles can be further enhanced by the application of a photographic silver emulsion (11,12,14,41,52).Colloidal gold particles of different sizes can be easily produced (24,50,54) and macromolecules such as enzymes, antibodies, lipoproteins, and hormones can be directly adsorbed on their surfaces (10,15,22,28) without modification of their biochemical and physiological properties (18,42,44,47,49,55). The one known exception 387 388 CATHIENI, TABAN is catalase (27).…”

mentioning

confidence: 99%

Microwave-aided binding of gold-protein-ligand (GPL) complexes. Light microscopic observations in the rat brain.

Cathieni¹,

Taban²

1992

J Histochem Cytochem.

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We describe a rapid method for the preparation and binding site labeling of cryostat sections for use in light microscopy. Instead of using antibodies to bind to specific sites, substance P, delta-sleep-inducing peptide, oxytocin, and dopamine were covalently attached to BSA and then the BSA-ligand complex was adsorbed on 5-nm colloidal gold particles. Bioassays carried out on isolated organs indicated that the physiological activity of the ligand GPL complex was maintained. Most of the technical steps included use of an ordinary microwave oven (MWO), with tissues exposed for less than 1 min in any given step. Cryostat sections of unfiied rat brain were pre-incubated for 50 sec in the MWO in a 'Iris-buffered solution (pH 7.4) containing 1.5% BSA, then further incubated for 50 sec in the MWO in Tris-buff e d solution containing 1% gelatin and the diluted colloidal IntroductionA number of bioactive molecular ligands can bind specific cell receptors and this binding may in turn activate cell functions not expressed in the absence of the binding signal. Detecting the distribution of specific cell binding sites at the light microscopic (LM) level can therefore provide useful information on the ability of a cell population to bind a given ligand, and possibly to respond to this binding when the bound site is part of a cell receptor (3,8,16,65). At present most such histological studies are carried out using autoradiographic (2,33) or immunocytochemical methods (9,61), but these techniques have certain inherent constraints.Application of autoradiography to light and electron microscopy allows an in situ study of the distribution of specific binding sites. However, ligand radiolabeling may modlfy results of the cell binding (26), and the quality of autoradiographs depends on several technical conditions related to tissue preparation, incubation medium, time of exposure, dispersion of the emitted rays, and sensitivity of the photographic film or radiosensitive emulsion (16,31). When unfixed tissue sections are used, the relatively long period ' Correspondence to: Dr. C. H. Tiban, Laboratory of Neurobiology, IUPG, 2 ch. Petit Bel-Air CH-1225 Chene-Bourg, Geneva, Switzerland. gold suspension. M e r washing, the preparations were postf i e d for 30 sec in the MWO in 5 Yo formaldehyde solution, pH 7.4. Finally, the cell-bound gold particles were enlarged by a silver-enhancing process and counterstained. Preparations observed at high magnification provided excellent resolution of the cell binding sites. Positive and negative controls performed by addition of BSA-conjugated ligands to the pre-incubation and incubation medium, and displacement of the markers by an excess of unbound ligand in the pre-incubation or the incubation medium, showed the specificity of the tissue labeling. ( J hlistochem Cytochem 40: 387-401, 1992)KEY WORDS: Light microscopy; Gold-protein-ligand complex; Binding site: Microwave-aided technique: Brain; Spinal cord: Rat.of incubation currently required (several minutes to hours) may itself modlfy the ...

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In vivo binding and uptake of low-density lipoprotein-gold- and albumin-gold conjugates by parenchymal and sinusoidal cells of the fetal rat liver

Cited by 9 publications

References 20 publications

Low-Density Lipoprotein Catabolism does not Respond to Estrogen in the Fetal and Newborn Rat

Low-Density Lipoprotein Catabolism does not Respond to Estrogen in the Fetal and Newborn Rat

Lipid raft‐dependent endocytosis of metallothionein in HepG2 cells

Microwave-aided binding of gold-protein-ligand (GPL) complexes. Light microscopic observations in the rat brain.

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