Renal Handling of Albumin: Clearance Studies with Bovine and Rat Serum Albumin in Conscious Rats1

2015 ◽  
pp. 225-230 ◽  
Author(s):  
H. Hackbarth ◽  
J. M. Alt ◽  
K. G�rtner ◽  
H. Sindermann
Keyword(s):  
Serum Albumin ◽  
Rat Serum ◽  
Renal Handling ◽  
Clearance Studies ◽  
Albumin Clearance ◽  
Rat Serum Albumin

Increased albumin and normal dextran clearances in protein-overload proteinuria in the rat

1985 ◽  
Vol 69 (3) ◽  
pp. 321-326 ◽  
Author(s):  
David J. Bliss ◽  
Douglas B. Brewer
Keyword(s):  
Serum Albumin ◽  
Glomerular Filtration Barrier ◽  
Rat Serum ◽  
Renal Handling ◽  
Permeability Characteristics ◽  
Filtration Barrier ◽  
Female Wistar Rats ◽  
Endogenous Albumin ◽  
Circulating Levels ◽  
Rat Serum Albumin

1. Female Wistar rats were made heavily proteinuric by daily intraperitoneal injections of bovine serum albumin over 5 days. 2. The size and charge permeability characteristics of the glomerular filter in this condition were determined by studying the renal handling of poly-dispersed uncharged dextran over the range of molecular radii 2–6 nm (albumin 3.6 nm), and of endogenous rat serum albumin over the same clearance period. 3. In proteinuric rats the clearance of rat serum albumin was significantly increased with a resultant reduction in the circulating levels of rat serum albumin. The clearance of uncharged dextran was not significantly different in proteinuric rats compared with control animals. 4. There does not appear to be any size selective defect of the glomerular filtration barrier in this condition. This suggests that the observed increase in the clearance of the negatively charged endogenous albumin may be due to a reduction in the glomerular charge barrier.

scholarly journals The Biosynthesis of Rat Serum Albumin

1972 ◽  
Vol 247 (12) ◽  
pp. 3858-3863 ◽  
Author(s):  
Theodore Peters ◽  
James C. Peters
Keyword(s):  
Serum Albumin ◽  
Rat Serum ◽  
Rat Serum Albumin

scholarly journals Bilirubin/Rat Serum Albumin Interaction.

1986 ◽  
Vol 40b ◽  
pp. 55-59 ◽  
Author(s):  
Peder C. Frandsen ◽  
Rolf Brodersen ◽  
Toshiaki Nishida ◽  
Curt R. Enzell ◽  
Synnøve Liaaen-Jensen ◽  
...  
Keyword(s):  
Serum Albumin ◽  
Rat Serum ◽  
Rat Serum Albumin

scholarly journals Upstream region of rat serum albumin gene promoter contributes to promoter activity: presence of functional binding site for hepatocyte nuclear factor-3

1999 ◽  
Vol 338 (2) ◽  
pp. 241-249 ◽  
Author(s):  
Chin-Hui HSIANG ◽  
Norman W. MARTEN ◽  
Daniel S. STRAUS
Keyword(s):  
Serum Albumin ◽  
Hepg2 Cells ◽  
Promoter Activity ◽  
Gene Promoter ◽  
Upstream Region ◽  
Nuclear Factor ◽  
Hepatocyte Nuclear Factor ◽  
Rat Serum ◽  
Albumin Gene ◽  
Rat Serum Albumin

Transcription of the serum albumin gene occurs almost exclusively in the liver and is controlled in part by a strong liver-specific promoter. The upstream region of the serum albumin gene promoter is highly conserved among species and is footprinted in vitro by a number of nuclear proteins. However, the role of the upstream promoter region in regulating transcription and the identity of the transcription factors that bind to this region have not been established. In the present study, deletion analysis of the rat serum albumin promoter in transiently transfected HepG2 cells demonstrated that elimination of the region between -207 and -153 bp caused a two-fold decrease in promoter activity (P< 0.05). Additional analysis of the -207 to -124 bp promoter interval led to the identification of two potential binding sites for hepatocyte nuclear factor-3 (HNF-3) located at -168 to -157 bp (site X) and -145 to -134 bp (site Y). Electrophoretic mobility-shift assays performed with the HNF-3 X and Y sites demonstrated that both sites are capable of binding HNF-3α and HNF-3β. Placement of a single copy of the HNF-3 X site upstream from a minimal promoter increased promoter activity by about four-fold in HepG2 cells, and the reporter construct containing this site could be transactivated if co-transfected with an HNF-3 expression construct. Furthermore, inactivation of the HNF-3 X site by site-directed mutagenesis within the context of the -261 bp albumin promoter construct resulted in a 40% decrease in transcription (P< 0.05). These results indicate that the positive effect of the -207 to -153 bp promoter interval is attributable to the presence of the HNF-3 X site within this interval. Additional results obtained with transfected HepG2 cells suggest that the HNF-3 Y site plays a lesser role in activation of transcription than the X site.

Megalin/gp330 mediates uptake of albumin in renal proximal tubule

1996 ◽  
Vol 271 (4) ◽  
pp. F900-F907 ◽  
Author(s):  
S. Cui ◽  
P. J. Verroust ◽  
S. K. Moestrup ◽  
E. I. Christensen
Keyword(s):  
Bovine Serum Albumin ◽  
Ligand Binding ◽  
Serum Albumin ◽  
Proximal Tubule ◽  
Proximal Tubules ◽  
Rat Serum ◽  
Gold Particles ◽  
Receptor Associated Protein ◽  
Rat Serum Albumin

Serum albumin filtered in renal glomeruli is reabsorbed very efficiently in the proximal tubule by endocytosis. The present study was undertaken to determine whether megalin/gp330 binds and mediates endocytosis of albumin. Rat serum albumin (RSA) labeled with 125I and colloidal gold particles labeled with bovine serum albumin (BSA) were microinfused into rat surface proximal tubules in vivo, and tubular uptake was determined in the presence or absence of different substances known to interfere with ligand binding to megalin. Binding of 125I-BSA and 125I-RSA to purified megalin was also determined directly using Sepharose columns. The results revealed that the tubular uptake of 125I-labeled RSA was significantly inhibited by receptor-associated protein (RAP), which reduced the uptake by > 50% and by cold RSA. The uptake of BSA gold by the proximal tubule was very intensive. BSA gold was found in small and large endocytic vacuoles, dense apical tubules, and in lysosomes. The uptake was reduced by RAP to 17%, by EDTA to 19%, by BSA to 16%, by megalin to 35%, by cytochrome c to 49%, and, together with gentamicin, there was virtually no uptake. Megalin-Sepharose columns bound 125I-labeled BSA as well as 125I-RSA, the binding was inhibited by RAP and EDTA, and analysis of the eluate revealed the bound tracer to be albumin. In conclusion, the present study demonstrates that megalin is a mediator of albumin reabsorption in renal proximal tubules.

scholarly journals LOCALIZATION OF POLYSOME-BOUND ALBUMIN AND SERINE DEHYDRATASE IN RAT LIVER CELL FRACTIONS

1973 ◽  
Vol 59 (1) ◽  
pp. 28-44 ◽  
Author(s):  
Yukio Ikehara ◽  
Henry C. Pitot
Keyword(s):  
Serum Albumin ◽  
Rat Liver ◽  
Significant Degree ◽  
Rabbit Serum ◽  
Chow Diet ◽  
Rat Serum ◽  
Fab Fragments ◽  
Serine Dehydratase ◽  
Membrane Bound ◽  
Rat Serum Albumin

The polysomes involved in albumin and serine dehydratase synthesis were identified and localized by the binding to rat liver polysomes of anti-rat serum albumin and anti-serine dehydratase [125I]Fab dimer and monomer. Techniques were developed for the isolation of undegraded free and membrane-bound polysomes and for the preparation of [125I]Fab monomers and dimers from the IgG obtained from the antisera to the two proteins, rat serum albumin and serine dehydratase. The distribution of anti-rat serum albumin [125I]Fab dimer in the polysome profile is in accordance with the size of polysomes that are expected to be synthesizing albumin. By direct precipitation, it has been demonstrated that nascent chains isolated from the membrane-bound polysomes by puromycin were precipitated by anti-rat serum albumin-IgG at a level of 5–6 times those released from free polysomes. Anti-rat serum albumin-[125I]Fab dimer reacted with membrane-bound polysomes almost exclusively compared to the binding of nonimmune, control [125I]Fab dimer; a significant degree of binding of anti-rat serum albumin-[125I]Fab to free polysomes was also obtained. The [125I]Fab dimer made from normal control rabbit serum does not react with polysomes from liver at all and this preparation will not interact with polysomes extracted from tissues that do not synthesize rat serum albumin. Both anti-serine dehydratase-[125I]Fab monomer and dimer react with free and bound polysomes from livers of animals fed a chow diet or those fed a high 90% protein diet and given glucagon. In the latter instance, however, it is clear that the majority of the binding occurs to the bound polysomes. Furthermore, the specificity of this reaction may be further shown by the use of kidney polysomes that do not normally synthesize serine dehydratase. When these latter polysomes are isolated, even after the addition of crude and purified serine dehydratase, no reaction with anti-serine dehydratase-Fab fragments could be demonstrated. These results indicate that the reaction of the Fab fragments are specific for polysomes that synthesize rat serum albumin or rat liver serine dehydratase. Furthermore, they demonstrate that even with this high degree of specificity, some polysomes in the fraction labeled "free" are in the process of synthesizing rat serum albumin while bound polysomes to a significant, if not major, degree are the site of the synthesis of rat liver serine dehydratase.

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