Migration of lymphoid cells to the bone marrow of rat following eradication of cells in DNA synthesis and in mitosis.

Eradication of replicating bone marrow cells of rat by means of combined administration of single doses of hydroxyurea and vinblastin is followed within 9--10 h by an inflow of lymphoid cells of extramedullary origin in the range of 13,200,000/femur. The rat bone marrow with a high content of lymphoid cells was previously shown to be concentrated in stem cells. The factor(s) which convey the 'information' of decrease of replicating marrow cells to extramedullary sites is at present unknown.