Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The iron status of a population of 1564 subjects living in the northwestern United States was evaluated by measurements of transferrin saturation, red cell protoporphyrin, and serum ferritin. The frequency distribution of these parameters showed no distinct separation between normal and iron-deficient subjects. When only one of these three parameters was abnormal (transferrin saturation below 15%, red cell protoporphyrin above 100 mug/ml packed red blood cells, serum ferritin below 12 ng/ml), the prevalence of anemia was only slightly greater (10.9%) than in the entire sample (8.3%). The prevalence of anemia was increased to 28% in individuals with two or more abnormal parameters, and to 63% when all three parameters were abnormal. As defined by the presence of at least two abnormal parameters, the prevalence of iron deficiency in various populations separated on the basis of age and sex ranged from 3% in adolescent and adult males to 20% in menstruating women. It is concluded that the accuracy of detecting iron deficiency in population surveys can be substantially improved by employing a battery of laboratory measurements of the iron status.
 ...
PMID:Evaluation of the iron status of a population. 95 65

Two iron-binding proteins were isolated from rat intestinal mucosa. From determination of their molecular weights, their electrophoretic and iron-binding properties it was established that one was a mucosal ferritin and the other a mucosal transferrin. The mucosal ferritin is compared in its molecular weight, isoelectric point, amino acid composition and tryptic peptide pattern with the ferritins of rat spleen and liver. All three ferritins are distinctly different from one another. In addition the iron content of mucosal ferritin was found to be much lower than that of liver and spleen ferritins. Mucosal transferrin was separated into two components by isoelectric focusing, as was plasma transferrin. The plasma and mucosal transferrins differ in their isoelectric points and in their amino acid compositions. Differences were also found in vitro in the iron-binding of mucosal transferrin as compared with plasma transferrin. The role of these mucosal proteins in the absorption of iron is briefly discussed.
 ...
PMID:Isolation and characterization of iron-binding proteins from rat intestinal mucosa. 95 50

Serum ferritin has been estimated in 125 untreated patients with Hodgkin's disease. Increasing concentrations are found at each advancing stage of the disease and high concentrations are found in patients with systemic symptoms. In all cases this is associated with a low serum Fe concentration and reduced transferrin saturation. There is no relationship between serum ferritin concentration and histological type of disease. The findings are compatible with a non-specific response of the reticuloendothelial system to malignancy, producing a secondary disorder of Fe metabolism.
 ...
PMID:Serum ferritin concentration in untreated Hodgkin's disease. 96 93

The ferritin content of monocytes, lymphocytes and polymorphs is reduced in patients with iron deficiency anaemia. In patients with the anaemia of chronic disease a reduced serum iron concentration is associated with an increase in the ferritin content of all peripheral blood leucocytes. Iron uptake by all cell types is related to transferrin saturation. In iron deficiency anaemia lymphocyte iron uptake is greatly increased, possibly relfecting intracellular iron depletion. In patients with active rheumatoid arthritis and carcinomatosis there is no alteration in leucocyte iron uptake or ferritin synthesis.
 ...
PMID:Iron uptake and ferritin synthesis by peripheral blood leucocytes from normal subjects and patients with iron deficiency and the anaemia of chronic disease. 97 35

The biological relevance of four iron-containing fractions previously detected in rat intestinal mucosal cells has been studied. The distribution of iron in these fractions obtained by chromatography on Sepharose 6B has been examined after in vivo and in vitro incubation of mucosal cells with 59Ce. In addition, the effects of phenobarbitone, cycloheximide, iron-deficiency and iron-loading on the uptake and distrubution of iron within the four mucosal cell fractions was studied. The iron in fraction I was mostly bound to intracellular membrane particles. Fraction II was shown to be ferritin. Fraction III contained some transferrin and also a protein of molecular weight similar to transferrin but which was not precipitable by antitransferrin antiserum. Quantited with the results of 'chaser' experiments suggested that, in addition to ferritin, at least two of the fractions (I and III) were involved in the process of iron absorption by the mucosal cell.
 ...
PMID:Iron absorption in the rat: the search for possible intestinal mucosal carriers. 97 37

The investigation of chelating agents with potential therapeutic value in patients with transfusional iron overload has been facilitated by the use of Chang cell cultures. These cells have been incubated with [59Fe]transferrin for 22 hr, following which most of the intracellular radioiron is found in the cytosol, distributed between a ferritin and a nonferritin form. Iron release from the cells depends on transferrin saturation in the medium, but when transferrin is 100% saturated, which normally does not allow iron release, desferrioxamine, 2,3-dihydroxybenzoic acid, rhodotorulic acid, cholythydroxamic acid, and tropolone all promote the mobilization of ferritin iron and its release from cells. They are effective to an approximately equal degree. The incubation of [59Fe]transferrin with tropolone in vitro at a molar ratio of 1:500 results in the transfer of most of the labeled iron to the chelator, reflecting the exceptionally high binding constant of this compound. How far these phenomena relate to therapeutic potentially remains to be seen.
 ...
PMID:The effect of chelating agents on iron mobilization in Chang cell cultures. 100 84

This paper reviews and reports the results of experiments on the mechanism by which iron is delivered from extracellular transferrin to reticulocyte mitochondria in which haem is synthesized. It is suggested that transferrin donates the iron directly to mitochondria. Transferrin seems to be bound to mitochondria during the process of iron release. When the release of iron from transferrin is blocked by haem, the iron-transferrin complex remains bound to mitochondria so that the total amount of transferrin molecules associated with mitochondria increases in haem-treated reticulocytes. This also leads to an increase in the number of transferrin molecules in the cytosol. In haem-deficient reticulocytes, the rate of dissociation of iron from transferrin is accelerated and the uptake of iron by mitochondria is increased. When the synthesis of haem is inhibited, the non-haem iron in the cytosol (i.e. mainly low-molecular-weight and ferritin iron) comes from mitochondria. Greater amounts of non-haem iron can also be induced in reticulocytes incubated with highly saturated transferrin but, in this case, iron does not seem to be accumulated in mitochondria. These results represent an experimental basis for the elucidation of the excessive non-haem iron accumulation in erythroid cells observed in various clinical conditions.
 ...
PMID:Control of iron delivery to haemoglobin in erythroid cells. 105 29

It seems likely that iron which has crossed the cell membrane and has been released from transferrin enters a labile intermediate pool from which it is available for haem synthesis, for the activation of iron-dependent enzymes, for incorporation into ferritin or for a return to extracellular transferrin. Enlargement of this pool stimulates ferritin synthesis. Iron probably enters the transit pool not only from transferrin but also as a result of endogenous haem breakdown and the mobilization of ferritin iron. Evidence for the occurrence of the transit pool has been obtained for reticuloendothelial cells, red cells precursors, cultured Chang cells and liver. It is suggested that the transit pool consists of a low molecular weight complex and that this is a major source of the iron chelated by agents such as desferrioxamine. No more precise characterization has been possible up to the present time.
 ...
PMID:An intracellular transit iron pool. 105 40

Iron atoms from the two iron-binding sites of transferrin in the maternal plasma were selectively transferred to fetal tissues across the placenta of the pregnant rat. Rat serum transferrin was selectively double-labeled with 55Fe bound to the A-site and 59Fe bound to the B-site and injected intravenously into pregnant rats at 11 to 20 days gestation. Ratios of 55Fe to 59Fe were measured in various maternal and fetal tissues sampled from 30 to 120 minutes after injection. In the maternal tissues preponderance of A-site 55Fe was observed in circulating red blood cells and in heme extracted from bone marrow and spleen; B-site 59Fe predominated in the liver parenchymal cells and proximal small intestine. As predicted by the Fletcher-Huehns hypothesis, placental transfer of radioiron resulted in a selective concentration of A-site 55Fe in all the fetal tissues including the fetal placenta, yolk sac, whole fetus, and in the separately analyzed liver heme and ferritin and in fetal blood. When the placenta was bypassed by direct injection of the selectively double-labeled transferrin into the umbilical vein, a reversal of the 55Fe/59Fe ratios of heme extracted from the fetal liver was observed. These studies confirm the concept of functional heterogeneity of iron atoms bound to transferrin and indicate that the placenta of rats between the eleventh and twentieth day of pregnancy selectively removes erythroblast-oriented iron from transferrin and diverts it to fetal tissues.
 ...
PMID:In vivo evidence for the functional heterogeneity of transferrin-bound iron. II. Studies in pregnant rats. 112 59

This paper describes a study of the incorporation of 59-Fe from 59-Fe-labelled rat transferrin into rat bone marrow cells in culture. 59-Fe was found in both stroma and cytoplasm of marrow cells, and the cytoplasmic 59-Fe separated by polyacrylamide gel electrophoresis, into ferritin, haemoglobin and a low molecular weight fraction. The incorporation of 59-Fe into all three cytoplasmic fractions, but not into the stroma, increased progressively with time. Erythropoietin stimulated the increase of 59-Fe in ferritin within 1 h, the earliest time examined, and more than 3 h later in the stroma and haemoglobin. A proportion of the 59-Fe incorporated into the stroma and low molecular weight iron fractions during a 1 h incubation with 59-Fe-labelled transferrin was mobilised into ferritin and haemoglobin during a subsequent 4-h "cold-chase". Erythropoietin, when present during the "cold-chase", did not influence these 59-Fe fluxes. The erythropoietin stimulation of 59-Fe incorporation into ferritin, one of the earliest erythropoietin effects to be recorded, was therefore considered to be due to an increase of 59-Fe uptake by the hormone-responsive cells rather than a direct effect on ferritin synthesis. 20-h cultures containing erythropoietin when incubated with 59-Fe-labelled transferrin for 4 h, showed dose-related erythropoietin stimulation of 59-Fe incorporation into haemoglobin only. In the presence of 10 mM isonicotinic acid hydrazide, 59-Fe incorporation into haemoglobin was inhibited, as in reticulocytes (Ponka, P. and Neuwrit, J. (1969) Blood 33, 690-707), while that into the stroma, ferritin and low molecular weight iron fractions, was stimulated; there were no reproducible effects of erythropoietin.
 ...
PMID:Erythropoietin effects on iron metabolism in rat bone marrow cells. 112 27


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>