Turnover Studies of Human β2-Microglobulin in the Rat: Evidence for a β2-Microglobulin-Binding Plasma Protein

1982 ◽  
Vol 62 (4) ◽  
pp. 403-410 ◽  
Author(s):  
H. Nguyen-Simonnet ◽  
C. Vincent ◽  
C. Gauthier ◽  
J. P. Revillard ◽  
M. V. Pellet
Keyword(s):  
Plasma Protein ◽  
Protein Turnover ◽  
Renal Arteries ◽  
Plasma Component ◽  
Major Site ◽  
Β2 Microglobulin ◽  
Additional Peak ◽  
The Difference ◽  
Binding Plasma Protein

1. 123I-labelled β2-microglobulin (β2m) was injected into rats and protein or non protein-bound radioactivity was determined in plasma urine and several organs. 2. The observed kinetics differed from those expected according to the bicompartmental model for plasma protein turnover. The difference was attributed to the binding of a part of the tracer to a plasma component. Chromatography of plasma taken after injection of β2m showed an additional peak of radioactivity at the 55 000–80 000 daltons position. 3. In animals with ligated renal arteries, disappearance of the tracer from the plasma was markedly prolonged, and little non-protein-bound radioactivity was detectable in plasma, indicating that the kidney was the major site of catabolism of β2m. 4. Chromatography of plasma from control rats and rats with ligated renal arteries showed that the kidney was the major site of catabolism for free β2m only. 5. In normal rats, the urine was found to contain only non-protein-bound radioactivity.

scholarly journals PLASMA PROTEIN TURNOVER AND TISSUE EXCHANGE

1959 ◽  
Vol 109 (2) ◽  
pp. 173-186 ◽  
Author(s):  
C. L. Yuile ◽  
F. V. Lucas ◽  
J. P. Olson ◽  
A. B. Shapiro
Keyword(s):  
Plasma Protein ◽  
Dietary Protein ◽  
Protein Turnover ◽  
Nitrogen Retention ◽  
Total Plasma ◽  
Protein Breakdown ◽  
Protein Levels ◽  
Total Plasma Protein ◽  
Protein Feeding ◽  
The Difference

The rate of plasma protein turnover is more rapid in dogs receiving adequate dietary protein than when a diet devoid of protein is fed. Both albumin and combined globulins are involved in this change. The difference in turnover is reflected in a total protein half-life of 4.8 days with protein feeding versus 7.8 days without protein in the diet and in the metabolism of 1.0 and 0.65 gm. per kilogram of body weight per day on the respective diets. Additions of dietary protein from 10 to 30 per cent caused no further increase in the rate of plasma protein turnover. With protein depletion due to plasmapheresis and a very low protein diet there is evidence of reduced protein metabolism as indicated by nitrogen retention as well as a reduction in total plasma protein breakdown and interchange of isotope between plasma and tissue proteins. Following introduction of labeled plasma protein into the circulation the net amount of isotope transferred to tissues has been computed from the difference between total plasma protein breakdown and combined C14 excretion in urine and expired air. In animals receiving adequate dietary protein, tissue transfer amounts to 70 per cent of the total lost from the plasma proteins each day while the percentage rises to 85 in depleted dogs deprived of protein. In dogs with both plasma and tissue proteins labeled it can be estimated that, under conditions of protein feeding, an amount of C14 approximately equal to that lost from the plasma must recycle to account for the observed decrease in Apparent plasma protein turnover rate, (t½ of 15 versus 5 days). Without protein in the diet the isotope contribution of the tissues to the maintenance of plasma protein levels must be as great as or greater than that transferred in the opposite direction.

Changes in glomerular filtration rate, lithium clearance and plasma protein clearances in the early phase after unilateral nephrectomy in living healthy renal transplant donors

1988 ◽  
Vol 75 (6) ◽  
pp. 655-659 ◽  
Author(s):  
S. Strandgaard ◽  
A. Kamper ◽  
P. Skaarup ◽  
N. H. Holstein-Rathlou ◽  
P. P. Leyssac ◽  
...  
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Protein ◽  
Immunoglobulin G ◽  
Filtration Rate ◽  
Early Response ◽  
Unilateral Nephrectomy ◽  
Lithium Clearance ◽  
Β2 Microglobulin ◽  
Observation Period

1. Glomerular and tubular function was studied before and 2 months after unilateral nephrectomy in 14 healthy kidney donors by measurement of the clearances of 51Cr-labelled ethylenediaminetetra-acetate, lithium, β2-microglobulin, albumin and immunoglobulin G. 2. The glomerular filtration rate (GFR) of the kidney that remained in the donor rose from 45 ± 10 (mean ± sd) to 59 ± 10 ml/min (P < 0.01) 5 days after contralateral nephrectomy and remained at this level through the observation period. 3. The lithium clearance (CLi) of the remaining kidney rose from 11.6 ± 3.7 to 20.5 ± 8.2 ml/min (P < 0.01) and remained significantly elevated throughout the observation period. 4. Absolute proximal fluid reabsorption rate (APR), which was estimated as GFR minus CLi, was unchanged 5 days after contralateral nephrectomy, but then rose gradually to reach significantly elevated levels after 4 weeks. 5. Fractional proximal reabsorption (FPR; APR/GFR) fell from 0.75 ± 0.06 to 0.66 ± 0.11 (P < 0.01) but subsequently rose to levels not significantly decreased from normal. 6. Twenty-four hour fractional clearances of β2-microglobulin, albumin and immunoglobulin G rose markedly on the day of nephrectomy, peaked at 2–3 days and subsequently fell to moderately elevated levels. 7. Both the CLj and the plasma protein clearance studies demonstrate that the early response of the remaining kidney to contralateral nephrectomy in man is an increase in GFR, an unchanged APR and a fall in FPR. The proximal tubules thus initially handle the increased filtrate load by passing it on to more distal nephron segments. Within 2–4 weeks, an adaptive increase is seen in proximal reabsorption of both protein and fluid, resulting in an almost complete normalization of glomerulotubular balance.

Further characterization and immunological studies of human sex steroid binding plasma protein

1979 ◽  
Vol 11 (1) ◽  
pp. 253-259 ◽  
Author(s):  
Christine Mercier-Bodard ◽  
Jack-Michel Renoir ◽  
Etienne-Emile Baulieu
Keyword(s):  
Plasma Protein ◽  
Sex Steroid ◽  
Steroid Binding ◽  
Binding Plasma Protein

Variation with age in the levels of sex-steroid-binding plasma protein as determined by radioimmunoassay

1984 ◽  
Vol 106 (3) ◽  
pp. 428-432 ◽  
Author(s):  
Yoshiyuki Maruyama ◽  
Norihiko Aoki ◽  
Yasuyuki Suzuki ◽  
Hyogo Sinohara ◽  
Toshio Yamamoto
Keyword(s):  
Pregnant Women ◽  
Plasma Protein ◽  
Sexual Difference ◽  
Sex Steroid ◽  
Blood Levels ◽  
Men And Women ◽  
Adult Men ◽  
Steroid Binding ◽  
Normal Men ◽  
Binding Plasma Protein

Abstract. A radioimmunoassay for human sex-steroidbinding plasma protein (SBP) was developed. With this assay, SBP was determined in sera of 138 normal men and 169 non-pregnant women, ranging in age from 11 to 87 years. The results indicate (i) that SBP levels in both sexes increase gradually with age up to mid-eighties, (ii) that the average levels in mid-eighties are approximately twice those in early twenties, and (iii) that the average levels in women are about twice as high as those in men of corresponding age. These results may also account for the discrepancies in the previous papers regarding the normal blood levels and sexual difference of SBP in adult men and women.

scholarly journals Immunofluorometric Point-of-Care Assays for the Detection of Acute Coronary Syndrome-Related Noncomplexed Pregnancy-Associated Plasma Protein A

2006 ◽  
Vol 52 (9) ◽  
pp. 1794-1801 ◽  
Author(s):  
Saara Wittfooth ◽  
Qiu-Ping Qin ◽  
Juha Lund ◽  
Ilkka Tierala ◽  
Kari Pulkki ◽  
...  
Keyword(s):  
Detection Limit ◽  
Plasma Protein ◽  
Specific Antibody ◽  
Point Of Care ◽  
Protein A ◽  
Serum Samples ◽  
Coronary Syndrome ◽  
A Subunit ◽  
The Difference ◽  
Eosinophil Major Basic Protein

Abstract Background: We recently reported that the pregnancy-associated plasma protein A (PAPP-A) form specifically related to acute coronary syndromes (ACS) is not complexed with the proform of eosinophil major basic protein (proMBP). The aim of this study was to develop rapid point-of-care immunoassays for the measurement of the noncomplexed PAPP-A. Methods: We developed immunofluorometric noncompetitive dry-reagent assays for total PAPP-A with 2 PAPP-A subunit-specific monoclonal antibodies and for PAPP-A/proMBP complex with 1 PAPP-A subunit-specific antibody and 1 proMBP subunit-specific antibody. The concentration of noncomplexed PAPP-A was determined as the difference of the results obtained with the 2 assays. Results: The assays were linear from 0.5 to 300 mIU/L. The analytical detection limit and functional detection limit (CV &lt;20%) were 0.18 mIU/L and 0.27 mIU/L for total PAPP-A assay and 0.23 mIU/L and 0.70 mIU/L for PAPP-A/proMBP assay, respectively. The total assay imprecisions were &lt;10%, and recoveries were 88%–107% for both assays. The mean difference (95% limits of agreement) between the new total PAPP-A assay and a previously reported total PAPP-A assay was −3.2% (−45.7% to 39.3%; n = 546; P = 0.0019). In serum samples from 159 non-ACS individuals, median concentrations (interquartile range) were 2.42 (1.14) mIU/L for total PAPP-A, 2.20 (1.18) mIU/L for PAPP-A/proMBP, and 0.18 (0.63) mIU/L for noncomplexed PAPP-A. Total PAPP-A and PAPP-A/proMBP, but not noncomplexed PAPP-A, correlated with age (r = 0.290, P = 0.0002; r = 0.230, P = 0.0035; r = 0.075, P = 0.3483, respectively). Conclusions: The new assays described revealed that noncomplexed PAPP-A is found only in negligible amounts in non-ACS samples.

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