The Plasma Clearance and Liver Uptake of Iron from Transferrin of Low and High Iron Saturation

1971 ◽  
Vol 41 (5) ◽  
pp. 395-402 ◽  
Author(s):  
J. Fletcher
Keyword(s):  
Plasma Clearance ◽  
Liver Uptake ◽  
Plasma Iron ◽  
High Iron ◽  
Iron Saturation ◽  
B Uptake

1. Serum labelled with radioactive iron was adjusted to different degrees of iron saturation and clearance of the tracer from the circulation of rats and its uptake by liver and intestine were followed. 2. The results showed that: (a) plasma iron clearance did not vary according to whether labelled iron was attached to transferrin at high or low iron saturation; (b) uptake of labelled iron by the liver was greater from transferrin at high iron saturation than from transferrin at low saturation. 3. The results suggest the presence of a receptor mechanism in the liver similar to that previously shown in reticulocytes.

The in Vivo Plasma Clearance of Iron from Transferrins of Low and High Iron Saturation

1970 ◽  
Vol 38 (6) ◽  
pp. 783-793 ◽  
Author(s):  
R. S. Lane ◽  
C. A. Finch
Keyword(s):  
Iron Uptake ◽  
Plasma Clearance ◽  
High Plasma ◽  
Clearance Time ◽  
Plasma Iron ◽  
High Iron ◽  
Iron Saturation ◽  
In Vivo Release ◽  
Iron Pool

1. The rate of in vivo release of iron from plasma transferrin samples at low and high saturation was measured simultaneously in fifteen subjects with differing amounts of body iron and different rates of erythropoiesis. Iron atoms bound to transferrin at low and high plasma iron saturation were identified by using tracer labels 55Fe and 59Fe respectively. Results were expressed as the plasma 55Fe and 59Fe half-clearance time. 2. Plasma iron clearance times ranged from 15·6 to 350 min, reflecting the different amounts of available iron and marrow requirements of the patients studied. The simultaneous rates of 55Fe and 59Fe clearance from the plasma were the same in thirteen patients. Clearances in two subjects showed differences between the two isotopes, but clearances of the identical paired isotopes in two other subjects showed no difference. 3. These results confirm earlier findings of homogeneity in the plasma iron pool, extending the observations to include varying per cent saturation of transferrin and varying rates of iron uptake.

Cholesteryl ester transfer protein (CETP) increases postprandial triglyceridaemia and delays triacylglycerol plasma clearance in transgenic mice

2009 ◽  
Vol 419 (3) ◽  
pp. 629-634 ◽  
Author(s):  
Alessandro G. Salerno ◽  
Patrícia R. Patrício ◽  
Jairo A. Berti ◽  
Helena C. F. Oliveira
Keyword(s):  
Cholesteryl Ester ◽  
Cholesteryl Ester Transfer Protein ◽  
Plasma Clearance ◽  
Low Density Lipoprotein ◽  
Lipoprotein Metabolism ◽  
Density Lipoprotein ◽  
Kinetic Studies ◽  
Cholesteryl Oleate ◽  
Liver Uptake ◽  
Transfer Protein

The CETP (cholesteryl ester transfer protein) is a plasma protein synthesized in several tissues, mainly in the liver; CETP reduces plasma HDL (high-density lipoprotein) cholesterol and increases the risk of atherosclerosis. The effect of CETP levels on postprandial intravascular metabolism of TAGs (triacylglycerols) is an often-overlooked aspect of the relationship between CETP and lipoprotein metabolism. Here, we tested the hypothesis that CETP delays the plasma clearance of TAG-rich lipoprotein by comparing human CETP expressing Tg (transgenic) and non-Tg mice. After an oral fat load, the postprandial triglyceridaemia curve was markedly increased in CETP-Tg compared with non-Tg mice (280±30 versus 190±20 mg/dl per 6 h respectively, P<0.02). No differences in intestinal fat absorption and VLDL (very-low-density lipoprotein) secretion rates were observed. Kinetic studies of double-labelled chylomicron-like EMs (emulsions) showed that both [3H]triolein and [14C]cholesteryl oleate FCRs (fractional clearance rates) were significantly reduced (∼20%) in CETP-Tg mice. Furthermore, TAG from lipid EM pre-incubated with CETP-Tg plasma had plasma clearance and liver uptake significantly lower than the non-Tg plasma-treated lipid EM. In addition, reductions in post-heparin plasma LPL (lipoprotein lipase) activity (50%) and adipose tissue mRNA abundance (39%) were verified in CETP-Tg mice. Therefore we conclude that CETP expression in Tg mice delays plasma clearance and liver uptake of TAG-rich lipoproteins by two mechanisms: (i) transferring TAG to HDLs and increasing CE content of the remnant particles and (ii) by diminishing LPL expression. These findings show that the level of CETP expression can influence the responsiveness to dietary fat and may lead to fat intolerance.

Modification of the plasma clearance and liver uptake of steroid ester-conjugated oligodeoxynucleotides by association with (lactosylated) low-density lipoprotein

2000 ◽  
Vol 59 (11) ◽  
pp. 1407-1416 ◽  
Author(s):  
Erik T Rump ◽  
Remco L.A de Vrueh ◽  
Muthiah Manoharan ◽  
Ingrid H.E Waarlo ◽  
Richard van Veghel ◽  
...  
Keyword(s):  
Plasma Clearance ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density ◽  
Liver Uptake

Impact of Feeding High-Iron Rice on Plasma Iron, Hemoglobin and Red Blood Cell Variables of Early-Weaned Piglets

2004 ◽  
Vol 48 (2) ◽  
pp. 109-117 ◽  
Author(s):  
Sebastian Schaffer ◽  
Josef Pallauf ◽  
Michael B. Krawinkel
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Weaned Piglets ◽  
Plasma Iron ◽  
High Iron

scholarly journals Duodenal Ferroportin Expression Is Unresponsive to Dietary Iron Excess in Nursing Piglets (FS04-01-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Peng Ji ◽  
Nicole Doan ◽  
Yining Wang ◽  
Eric Nonnecke ◽  
Bo Lonnerdal
Keyword(s):  
Birth Weight ◽  
Low Birth Weight ◽  
Protein Expression ◽  
Iron Overload ◽  
Transferrin Saturation ◽  
Pig Model ◽  
Dietary Iron ◽  
Plasma Iron ◽  
High Iron ◽  
Mrna And Protein Expression

Abstract Objectives In the US, prophylactic iron supplementation without thorough screening for iron deficiency is commonly practiced in both normal weight and low birth weight infants. In a nursing pig model, we previously found that excess dietary iron results in tissue iron overload, suggesting ineffective regulation of intestinal iron absorption. Herein, we aimed to determine if hepcidin-mediated ferroportin (FPN1) degradation is functionally immature in early life. Methods Twelve nursing piglets of normal birth weight (2.1 ± 0.4 kg, PD2) were supplemented with either low (AGAL, 1 mg/d·kg body weight) or high iron (AGAH, 15 mg/d·kg BW)) in form of ferrous sulfate solution. Eight low birth weight (1.2 ± 0.4 kg on PD2) piglets were supplemented with high iron (SGAH, 15 mg/d·kg BW) from PD2 to 21. All piglets were raised by suckling their sows. Blood samples were collected weekly for analysis of hemoglobin, hematocrit, and plasma iron. Duodenal mucosa (DM) and hepatic mRNA and protein expression of iron transporters and regulators were analyzed using RT-qPCR and Western blot. Data were analyzed using PROC MIXED of SAS with CONTRAST statement for planned comparison between AGAL and high iron groups. Results In comparison with AGAL, high iron, regardless of birth weight, significantly (P < 0.05) increased hemoglobin, transferrin saturation (74% vs. 49%), and plasma iron, and resulted in iron overload in DM and liver at PD21. Hepatic mRNA expression of HAMP and FTL in DM increased 275- and 3-fold, respectively, in response to high iron, whereas DMT1 in DM and TFRC in both liver and DM decreased by 7.4-, 3.8- and 5.3-fold, respectively. Consistently, protein expression of DMT1 in DM was lower in SGAH than that in AGAL; However, both mRNA and protein expression of FPN1 in DM and liver remained unaffected by iron provision or birth weight. Conclusions Hepcidin-induced ferroportin degradation is hypo-responsive to iron excess in a nursing pig model. Funding Sources UC Davis, NIFA.

Mechanisms of Pathogenesis in Listeria monocytogenes Infection IV. Hepatic Carbohydrate Metabolism and Function in Experimental Listeriosis

1970 ◽  
Vol 1 (2) ◽  
pp. 183-189
Author(s):  
R. E. McCallum ◽  
C. P. Sword
Keyword(s):  
Listeria Monocytogenes ◽  
Carbohydrate Metabolism ◽  
Plasma Clearance ◽  
Succinic Dehydrogenase ◽  
Liver Glycogen ◽  
Liver Function Tests ◽  
Liver Uptake ◽  
Listeria Monocytogenes Infection ◽  
Liver Homogenates ◽  
And Function

Previous reports have shown alterations in carbohydrate metabolism in mice infected with Listeria monocytogenes . This study was undertaken to elucidate mechanisms involved in these changes. Female CD-1 mice were injected intraperitoneally with 10 6 L. monocytogenes strain A4413. Animals were fasted 12 hr prior to infection, and pooled tissue from several mice was observed at intervals after infection. Blood glucose, liver glucose, and liver glycogen decreased within 10 hr after infection. Sustained treatment with gluconeogenic precursors, including glucose-6-phosphate, fructose-1, 6-biphosphate, phosphoenolpyruvate, α-glycerophosphate, pyruvate, and amino acids, did not restore and maintain glucose and glycogen at normal levels and did not affect survival. Administration of hydrocortisone induced restoration of liver glycogen early in the infection but did not maintain normal levels as the infection progressed. Activities of succinic dehydrogenase and cytochrome oxidase in liver homogenates from infected mice were elevated as early as 10 hr after infection. Liver function tests using rose bengal sodium- 131 I showed no significant differences in plasma clearance or liver uptake between normal and infected mice except in terminal infections (60 hr after infection).

Hepatobiliary Kinetics of 113mIn-Phenolphthalexon

1981 ◽  
Vol 20 (02) ◽  
pp. 90-93
Author(s):  
P.B. Parab ◽  
U.R. Raikar ◽  
R.D. Ganatra ◽  
M. C. Patel
Keyword(s):  
Biliary Excretion ◽  
Iminodiacetic Acid ◽  
Organ Distribution ◽  
Liver Uptake ◽  
On Line ◽  
Rapid Clearance ◽  
Chemical Purity ◽  
Kinetics Of ◽  
High Liver

Phenolphthalexon, a compound with iminodiacetic acid as a functional group, has been labelled with 113mIn to high chemical purity and its usefulness in studies of biliary excretion patency has been studied. Organ distribution of 113mIn-phenolphthalexon in mice was characterized by high liver uptake (50.8% of the administered dose after 5 min) and rapid clearance through the gall bladder. An animal model for studying obstruction of biliary excretion has been developed. Data on the kinetics of the radiopharmaceutical were obtained by collecting in-vivo data through an on-line computer.

Catabolism of Human Fibrinogen Fragment D in Normal Subjects and Patients with Liver Cirrhosis

1980 ◽  
Vol 44 (03) ◽  
pp. 146-149 ◽  
Author(s):  
Nicole Ardaillou ◽  
Jeannine Yvart ◽  
Philippe Le Bras ◽  
Marie-José Larrieu
Keyword(s):  
Liver Cirrhosis ◽  
Clearance Rate ◽  
Plasma Clearance ◽  
Normal Subjects ◽  
Fractional Catabolic Rate ◽  
Human Fibrinogen ◽  
Plasma Pool ◽  
Catabolic Rate ◽  
Chloramine T

SummaryThe catabolism of human fragment D, (FgD), obtained by plasmin digestion of fibrinogen has been investigated in normal subjects and patients with liver cirrhosis and the results compared with those obtained for fibrinogen (Fg). Fg was labelled with I-125 and Fg D with I-131 using the chloramine T method. The plasma disappearance curves of both labelled proteins fitted a two exponential curve. In controls the plasma clearance rate of Fg D was greater than that of Fg as shown by the marked difference between the half-lives of these two tracers: 8,9 and 83,5 hours for Fg D and Fg respectively. The fractional catabolic rate of Fg D was 3.38 times the plasma pool per day. In nine patients with liver cirrhosis, catabolism of Fg was not modified. In contrast, catabolism of Fg D was significantly reduced with a half life of 13.0 hours and a low fractional catabolic rate. These results suggest the role of the liver in the catabolism of Fg D in man.

Uptake, Internalization and Degradation of the Novel Plasminogen Activator Reteplase (BM 06.022) in the Rat

1995 ◽  
Vol 74 (06) ◽  
pp. 1501-1510 ◽  
Author(s):  
J Kuiper ◽  
H van de Bilt ◽  
U Martin ◽  
Th J C van Berkel
Keyword(s):  
Plasminogen Activator ◽  
Liver Cells ◽  
The Novel ◽  
Uptake Mechanism ◽  
Liver Uptake ◽  
Lysosomal Compartment ◽  
Β Phase ◽  
Α Phase ◽  
Parenchymal Liver

SummaryThe catabolism of the novel plasminogen activator reteplase (BM 06.022) was described. For this purpose BM 06.022 was radiolabelled with l25I or with the accumulating label l25I-tyramine cellobiose (l25I-TC).BM 06.022 was injected at a pharmacological dose of 380 μg/kg b.w. and it was cleared from the plasma in a biphasic manner with a half-life of about 1 min in the α-phase and t1/2of 20-28 min in the β-phase. 28% and 72% of the injected dose was cleared in the α-phase and β-phase, respectively. Initially liver, kidneys, skin, bones, lungs, spleen, and muscles contributed mainly to the plasma clearance. Only liver and the kidneys, however, were responsible for the uptake and subsequent degradation of BM 06.022 and contributed for 75% to the catabolism of BM 06.022. BM 06.022 was degraded in the lysosomal compartment of both organs. Parenchymal liver cells were responsible for 70% of the liver uptake of BM 06.022. BM 06.022 associated rapidly to isolated rat parenchymal liver cells and was subsequently degraded in the lysosomal compartment of these cells. BM 06.022 bound with low-affinity to the parenchymal liver cells (550 nM) and the binding of BM 06.022 could be displaced by t-PA (IC50 5.6 nM), indicating that the low-density lipoprotein receptor-related protein (LRP) could be involved in the binding of BM 06.022. GST-RAP, which is an inhibitor of LRP, could in vivo significantly inhibit the uptake of BM 06.022 in the liver.It is concluded that BM 06.022 is metabolized primarily in the liver and the kidneys. These organs take up and degrade BM 06.022 in the lysosomes. The uptake mechanism of BM 06.022 in the kidneys is unknown, while LRP is responsible for a low-affinity binding and uptake of BM 06.022 in parenchymal liver cells.

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