Biomaterial Database

Hepatic uptake of iron by receptor-mediated and receptor-independent mechanisms. 1996

B Scheiber, and H Goldenberg

Institut für Medizinische Chemie, University of Vienna, Austria.

Hepatocytes can accumulate iron from transferrin via receptor- or non-receptor-mediated endocytosis or from non-transferrin iron complexes. The latter is several times more efficient than the transferrin-mediated uptake. Both pathways have some properties in common and mutually influence each other: Whereas on the one hand the non-permeant chelator DTPA as well as a polymer-conjugated desferrioxamine inhibit uptake of iron from transferrin, transferrin (in both forms, diferric or apo) itself inhibits uptake from the Fe(3+)-DTPA complex. At neutral pH, strong stimulation by reductant is observed, as well as inhibition by the prototropic agent chloroquine. This situation is reversed at acidic pH. Weak chelators stimulate uptake of iron from Fe-DTPA in hepatocytes. We conclude that the cell can labilize the chelate complex. The further mechanism of membrane passage is dependent on the environment. All the acquired iron can be found in ferritin.

UI	MeSH Term	Description	Entries
D007501	Iron	A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.	Iron-56,Iron 56
D007502	Iron Chelating Agents	Organic chemicals that form two or more coordination links with an iron ion. Once coordination has occurred, the complex formed is called a chelate. The iron-binding porphyrin group of hemoglobin is an example of a metal chelate found in biological systems.	Iron Chelates,Agents, Iron Chelating,Chelates, Iron,Chelating Agents, Iron
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D011990	Receptors, Transferrin	Membrane glycoproteins found in high concentrations on iron-utilizing cells. They specifically bind iron-bearing transferrin, are endocytosed with its ligand and then returned to the cell surface where transferrin without its iron is released.	Transferrin Receptors,Transferrin Receptor,Receptor, Transferrin
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D004705	Endocytosis	Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.	Endocytoses
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D051381	Rats	The common name for the genus Rattus.	Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus