Biomaterial Database

Transferrin receptor numbers and transferrin and iron uptake in cultured chick muscle cells at different stages of development. 1987

L M Sorokin, and E H Morgan, and G C Yeoh

The mechanism of iron uptake and the changes which occur during cellular development of muscle cells were investigated using primary cultures of chick embryo breast muscle. Replicating presumptive myoblasts were examined in exponential growth and after growth had plateaued. These were compared to the terminally differentiated cell type, the myotube. All cells, regardless of the state of growth or differentiation, had specific receptors for transferrin. Presumptive myoblasts in exponential growth had more transferrin receptors (3.78 +/- 0.24 X 10(10) receptors/micrograms DNA) than when division had ceased (1.70 +/- 0.14 X 10(10) receptors/micrograms DNA), while myotubes had 3.80 +/- 0.26 X 10(10) receptors/micrograms DNA. Iron uptake occurred by receptor-mediated endocytosis of transferrin. While iron was accumulated by the cells, apotransferrin was released in an undegraded form. There was a close correlation between the molar rates of endocytosis of transferrin and iron. Maximum rates of iron uptake were significantly higher in myotubes than in presumptive myoblasts in either exponential growth or after growth had plateaued. There were two rates of exocytosis of transferrin, implying the existence of two intracellular pathways for transferrin. These experiments demonstrate that iron uptake by muscle cells in culture occurs by receptor-mediated endocytosis of transferrin and that transferrin receptor numbers and the kinetics of transferrin and iron uptake vary with development of the cells.

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
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009132	Muscles	Contractile tissue that produces movement in animals.	Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
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
D002454	Cell Differentiation	Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.	Differentiation, Cell,Cell Differentiations,Differentiations, Cell
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
D002642	Chick Embryo	The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching.	Embryo, Chick,Chick Embryos,Embryos, Chick
D004705	Endocytosis	Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.	Endocytoses
D005089	Exocytosis	Cellular release of material within membrane-limited vesicles by fusion of the vesicles with the CELL MEMBRANE.
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