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.

Sarcolemmal disruption in reloaded atrophic skeletal muscle

1995 ◽  
Vol 79 (2) ◽  
pp. 607-614 ◽  
Author(s):  
C. E. Kasper
Keyword(s):  
Skeletal Muscle ◽  
Serum Albumin ◽  
Time Course ◽  
Intracellular Staining ◽  
Rat Serum ◽  
Cross Sectional ◽  
Membrane Rupture ◽  
Female Wistar Rats ◽  
Hind Limb Unloading ◽  
Rat Serum Albumin

The purpose of this study was to determine whether reloading of atrophied skeletal muscle after 28 days of hind-limb unloading (HU) would produce significant sarcolemmal membrane disruption before frank necrosis. Soleus and plantaris muscles were atrophied by HU. Adult female Wistar rats (N = 13) were killed at 28 days of unloading and 4 and 7 days of reloading after HU. Rat serum albumin was used as a marker for muscle fiber disruption. Dark intracellular staining with horseradish peroxidase-conjugated anti-rat serum albumin antibody was interpreted as evidence of membrane rupture. There was a significantly different time course of disruption between plantaris and soleus muscles, with a negative correlation between cell size and occurrence of disruption. Fourteen percent of plantaris fibers were wounded after HU, peaking at day 4 of reloading (20% of cross-sectional area). Soleus demonstrated disruption only on reloading peaking in severity at day 7 (14% of fibers). It was demonstrated that sarcolemmal disruption due to atrophy and reloading does not always progress to necrosis and degeneration by the 7th day of recovery.

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.

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