[Active transport of cobalamins in leukemic cells of L-1210 mice]

The Tc-II receptors of cell surface membrane and the cobalamins entering into the L-1210 mouse leukemia cells were investigated. We used the blood serum Tc-II saturated with 57CoCNCbl for radioactivity determination separately in solubilized receptors and inside of the cells. The data on ligand regulation of the leukemic cell membrane receptors number were received. The internalization of radioactive complex of Tc-II and cobalamin was revealed during intensive 3H-thymidine incorporation into DNA of the cultivated cells.