iron is essential to erythrocyte oxygen transport and is a catalyst for oxidative metabolism in all cells. iron is absorbed by the duodenum and requires an acidic environment for optimal absorption. iron is found for 70% in erythrocytes, and 30% in storage, and a small amount in myoglobin and cytochromes. iron supplementation reduces anemia in breastfed infants and increases in significant dose...

We have studied transferrin receptor expression in MRC5 human fibroblasts in response to tumor necrosis factor-alpha (TNF, cachectin) or interleukin 1-alpha (IL-1). Treatment of exponentially growing MRC5 cells with these cytokines led to a 3-4-fold increase in transferrin receptor mRNA and a coordinate increase in transferrin receptor protein by 24 h. Under these conditions, stimulation of [3H...

The toxic A chain of ricin was linked to human transferrin via a disulfide bond and the resulting conjugate was shown to bind to cell membrane transferrin receptors. Surface-localized transferrin A chain (TF-A chain) gained access to the cytoplasm and inactivated ribosomes as witnessed by a rapid curtailment of cellular protein synthesis (t1/2 = 6 h) and subsequent cytolysis. The intact conjuga...

Variations in either the polypeptide sequence or the carbohydrate moieties of transferrin may result in altered electrophoretic mobility of this molecule. We report a case of an allelic (polypeptide) variant of transferrin with mobility similar to that of the beta 2 (sialic acid-depleted) transferrin found in cerebrospinal fluid (CSF) and a few other body fluids. Allelic variation and other tra...

The uptake of iron from transferrin by isolated rat hepatocytes varies in parallel with plasma membrane NADH:ferricyanide oxidoreductase activity, is inhibited by ferricyanide, ferric, and ferrous iron chelators, divalent transition metal cations, and depends on calcium ions. Iron uptake does not depend on endosomal acidification or endocytosis of transferrin. The results are compatible with a ...

The effect of the known inhibitors of iron uptake, n-butylamine and NH4Cl, was examined at the molecular level to more precisely define the mechanisms by which these lysosomotropic agents block iron uptake by rabbit reticulocytes. Utilizing a rapid pulse-chase technique to follow the handling of a cohort of 59Fe, 125I-transferrin bound to rabbit reticulocytes, both amines were observed to have ...

1. Serum prealbumin, transferrin and iron concentrations were measured in ninety-two north Cameroonian children under 5 years of age. The results were grouped according to the blood haemoglobin concentration range in order to show the interactions of anaemia with prealbumin and transferrin concentrations. 2. Transferrin concentration showed a significant negative correlation with serum Fe and p...

Mycobacterium tuberculosis (M.tb), which requires iron for survival, acquires this element by synthesizing iron-binding molecules known as siderophores and by recruiting a host iron-transport protein, transferrin, to the phagosome. The siderophores extract iron from transferrin and transport it into the bacterium. Here we describe an additional mechanism for iron acquisition, consisting of an M...

Transferrin, an iron-transporting serum glycoprotein, is efficiently taken up into cells by the process of receptormediated endocytosis. Transferrin receptors are found on the surface of most proliferating cells, in elevated numbers on erythroblasts and on many kinds of tumors. The efficient cellular mechanism for uptake of transferrin has been subverted for the delivery of low-molecular-weight...

Here we investigate the regulation of hepcidin, a hormone that inhibits dietary iron absorption and macrophage iron recycling, by the serum iron-binding protein transferrin. Mice deficient in transferrin (Tf(hpx/hpx)) and hemojuvelin (Hjv(-/-)), a gene mutated in juvenile hemochromatosis, a disease of hepcidin deficiency and iron overload, were generated. While Tf(hpx/hpx) Hjv(+/+) and Tf(hpx/h...