Effect of iron and transferrin on pure oligodendrocytes in culture; characterization of a high-affinity transferrin receptor at different ages.

Oligodendrocytes in pure culture can grow on relatively low iron concentrations (0.1-0.3 microM), in the absence of transferrin; with micromolar concentrations of iron, toxic effects can be seen after one week in culture. When transferrin is added, the toxic effect of iron is increased. These properties account for the mode of selection of oligodendrocytes for pure cultures. Each oligodendrocyte presents between 1100 and 3600 receptor molecules, with a dissociation constant of 0.2-0.6 nM corresponding to a high affinity transferrin-binding site; these constants vary little with age in culture. These receptors may function as autoreceptors regulating transferrin synthesis by oligodendrocytes.