Cytological studies of plasma albumin in the rat liver

Chandrasekharan, N

doi:10.1007/bf00303871

Cited by 9 publications

(5 citation statements)

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“…For instance it is the case for albumin [19,20,33,35,44,45,47,48] and also for fibrinogen [19,33], haptoglobin [110], trans ferrin [111], ai-antitrypsin [10] or factor V [21], By contrast, in many other works [23, 24, 30-32, 34, 36, 37, 50, 53-55, 57, 58, 62], using either immunoperoxidase or in situ hybridization, no variation was reported from hepatocyte to hepatocyte. These discre pant results must be analyzed cautiously since, as pointed out above, technical condi tions can deeply influence the results of mor phological studies, perhaps more at the level of a single hepatocyte than at the level of a lobular zone.…”

Section: Hepatocellular Heterogeneity For Plasma Protein Synthesismentioning

confidence: 99%

“…From 1964, the date of the first publication on the localization of albumin [19], until now, at least 31 publications have been de voted to this subject. Analysis of these publi cations shows that in 12 of them [19,20,[44][45][46][47][48][49][50][51][52][53] a random distribution of albumin-syn thesizing hepatocytes was reported with sometimes a preferential localization of these cells around the portal triads or the centrilobular veins, while in 13 other publi cations [26,32,34,42,43,[54][55][56][57][58][59][60][61], albumin was visible in all hepatocytes with no lobular zonation, and in 9 publications [33,[35][36][37][38][39][40][41]62], albumin was also present in all hepato cytes, but with a porto-centrilobular gradient ( fig. 1,2).…”

Section: Zonal Lobular Heterogeneity For Plasma Protein Synthesismentioning

confidence: 99%

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Functional Hepatocellular Heterogeneity for the Production of Plasma Proteins

Feldmann

Scoazec²,

Racine³

et al. 1992

Enzyme

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It is now well established that hepatocytes are the main liver cells responsible for the synthesis of plasma proteins produced by the liver. That these cells are not specialized in the production of the different plasma proteins is also well established. Presently the point still debated is whether a functional hepatocellular heterogeneity exists for plasma protein synthesis as for many other hepatocyte functions. Several physiological and pathological situations suggest that this heterogeneity takes place in the hepatocytes of two opposite hepatic lobular zones, the periportal and centrilobular zones. However, this zonal difference, which supposes different regulatory mechanisms, must be confirmed by techniques other than the now classical immunocytochemistry or the in situ hypbridization technique recently proposed for the demonstration of mRNAs in hepatocytes. Another hepatocellular heterogeneity, the intercellular heterogeneity, which can be observed in the same lobular zone, is more difficult to analyze, but shows that from hepatocyte to hepatocyte a variation exists in the synthesis of a given plasma protein.

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Section: Hepatocellular Heterogeneity For Plasma Protein Synthesismentioning

confidence: 99%

Section: Zonal Lobular Heterogeneity For Plasma Protein Synthesismentioning

confidence: 99%

Functional Hepatocellular Heterogeneity for the Production of Plasma Proteins

Feldmann

Scoazec²,

Racine³

et al. 1992

Enzyme

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“…Previous immunohistochemical studies aimed at identifying albumin-containing cells in mammalian liver (human [6,7] ; pig [39]; and rat [3][4][5]40]) have produced conflicting results: the majority (3-7) indicated that only 10-50% of hepatocytes contain and, by implication, synthesize albumin ; a minority of the studies, one in newborn pigs (39) and the other in rats (40), reported that nearly all hepatocytes do contain albumin . All of these investigations involved immunocytochemical localization of albumin-containing cells in fixed, histologic sections of liver.…”

Section: Phenylalanine Hydroxylase and Albumin In Isolated Hepatocytesmentioning

confidence: 99%

“…Because the method, which we hoped also to apply in studies with perfused rat liver, involved the use of albumin as a reference protein, the question immediately arose as to whether or not albumin and phenylalanine hydroxylase were simultaneously synthesized within the same cells. Several studies (3)(4)(5)(6)(7) indicate that only a minority of liver parenchymal cells contain and, by implication, synthesize albumin. To our knowledge, there is no existing information regarding the distribution of phenylalanine hydroxylase among hepatic cells either in vivo or in culture.…”

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confidence: 99%

Immunocytochemical identification of phenylalanine hydroxylase and albumin in cultured hepatoma cells and isolated rat hepatocytes.

Baker

Jefferson²,

Shiman

1981

The Journal of Cell Biology

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Rhodamine-conjugated antibodies specific for phenylalanine hydroxylase and serum albumin were employed as cytochemical probes to identify these two proteins in H4 hepatoma cells and in isolated rat hepatocytes . Each fluorescent antibody stained the cells specifically and in a distinctive manner . In both cell types, albumin staining was discretely localized in cytoplasmic "bundles," whereas, phenylalanine hydroxylase staining was diffuse and cytoplasmic and in H4 cultures varied somewhat from cell to cell. Evidence from cultures of REB15 cells, a strain derived by cloning H4 cells in tyrosine-free medium, suggested that the staining variability of H4 cells could reflect a variability in phenylalanine hydroxylase content. Hydrocortisone-treated H4 and REB15 cultures contain increased amounts of phenylalanine hydroxylase ; and all cells in the culture appear to be induced by the hormone .Evidence was presented to show that the albumin visualized within the isolated hepatocytes had been synthesized by these cells, and, furthermore, that quantitatively nearly all intracellular albumin in the isolated rat hepatocytes appeared to be entrained in the secretion pathway (analogous data already exist for H4 cells [Baker, R. E ., and R. Shiman . 1979 . J . Biol . Chem. 254: [9633][9634][9635][9636][9637][9638][9639]) . By scoring specific fluorescence, 86 and 98% of the H4 cells and 89 and 98% of the isolated hepatocytes were found to contain phenylalanine hydroxylase and albumin, respectively . Therefore, almost all cells in each population appeared to synthesize both proteins . An implication of these findings is that in rat virtually all liver parenchymal cells must synthesize both phenylalanine hydroxylase and albumin .Serum albumin synthesis and phenylalanine hydroxylase expression are differentiated functions of normal mammalian liver . Both functions are also expressed by the Reuber hepatoma (rat) cell line H4 (1) . Recently, we developed a new method for measuring protein turnover and used it to determine the half-life of phenylalanine hydroxylase in H4 cultures (2). Because the method, which we hoped also to apply in studies with perfused rat liver, involved the use of albumin as a reference protein, the question immediately arose as to whether or not albumin and phenylalanine hydroxylase were simultaneously synthesized within the same cells. Several studies (3-7) indicate that only a minority of liver parenchymal cells contain and, by implication, synthesize albumin. To our knowledge, there is no existing information regarding the distribution of phenylalanine hydroxylase among hepatic cells either in vivo or in culture. To answer the cosynthesis question, THE JOURNAL Of CELL BIOLOGY " VOLUME 90 JULY 1981 145-152 ©The Rockefeller University Press " 0021-9525/81/07/0145/OB $1 .00 we employed immunocytochemical methods to identify albumin and phenylalanine hydroxylase in H4 cultures and also in freshly isolated rat hepatocytes. Our results, reported here, are of quite general interest, because they supply...

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“…The membrane-attached polysomes of the liver cells are assumed to be the intracellular site of albumin synthesis (for recent critical review see Campbell (1)) . The histological localization of albumin by fluorescent antisera has been described repeatedly (3,(5)(6)(7) . It is not possible, however, to decide whether albumin localized in the cell by this technique is newly synthesized, or taken up by the cells from the blood, or simply adsorbed during preparation .…”

Section: Introductionmentioning

confidence: 99%

The Distribution of Albumin Synthesis Throughout the Liver Lobule

Schreiber

Lesch

Weinssen

et al. 1970

The Journal of Cell Biology

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INTRODUCTIONThe membrane-attached polysomes of the liver cells are assumed to be the intracellular site of albumin synthesis (for recent critical review see Campbell (1)) . The histological localization of albumin by fluorescent antisera has been described repeatedly (3, 5-7) . It is not possible, however, to decide whether albumin localized in the cell by this technique is newly synthesized, or taken up by the cells from the blood, or simply adsorbed during preparation .In radioautographs we observed predominant labeling of the periportal area of the liver lobules after intraportal injection of leucine-3H, whereas intracaval injection led to uniform labeling throughout the lobule . The way of administration of the tracer thus permits a study of protein synthesis of selected regions of the liver lobule .Recently, the isolation of radiochemically pure albumin from liver homogenates and a method to determine the proportion of albumin to total protein synthesis have been described (9) .In this report the ratio of albumin to total protein synthesis after intraportal injection was compared to that after intracaval injection . By combining these results with the radioautographic observations, it was possible to decide whether or not albumin synthesis was distributed uniformly throughout the liver lobule . MATERIALS AND METHODSAnimals and biochemical methods have been described previously (8, 9) .For radioautography small pieces of liver were fixed in 0.75 M sodium phosphate buffer of pH 7 .0 with 4% formaldehyde for 24 hr at 4°C, dehydrated in ethanol, and embedded in paraffin blocks . Slices of 5 µ and control slices from unlabeled livers were cut and transferred to the same microscopical slides . Paraffin was removed by alcohol, methylbenzoate, and xylene. The slices were washed twice for 20 min in 0 .76 mm nonradioactive leucine and then dipped into Ilford K5 liquid emulsion (Ilford Ltd ., Ilford, Essex, England) . After 24 days' exposure at 18°C and after photographic development, radioautographs were stained through the emulsion with Mayer's hemalum, made transparent by 70% ethanol with 4 vol % of 1 N HCI, rinsed in running tap water, and dried .The density of silver grains was determined by leading a measuring diaphragm of 552 µ2 around the central and the periportal areas of the liver THE JOURNAL OF CELL BIOLOGY • VOLUME 47, 1970 • pages 285-289 285 on May 13, 2018 jcb.rupress.org Downloaded from http://doi.org/10.1083/jcb.47.1.285 Published Online: 1 October, 1970 | Supp Info:lobule and measuring the light reflected by the silver grains in a microscope equipped with a photomultiplier (4) . The pulses of the photomultiplier were recorded as "working units" by a Knott analog digital counter . Two animals were measured after intraportal, and two after intracaval injection of the label . Almost identical values were obtained within each group . The obtained values were averaged after subtraction of the background, which was determined with unlabeled slices . After intraportal injection, 100 positions of the diaph...

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Cytological studies of plasma albumin in the rat liver

Cited by 9 publications

References 9 publications

Functional Hepatocellular Heterogeneity for the Production of Plasma Proteins

Functional Hepatocellular Heterogeneity for the Production of Plasma Proteins

Immunocytochemical identification of phenylalanine hydroxylase and albumin in cultured hepatoma cells and isolated rat hepatocytes.

The Distribution of Albumin Synthesis Throughout the Liver Lobule

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