Megakaryocyte colony culture using a liver cell conditioned medium.

Megakaryocyte colonies may now be grown in semi-solid agar, agarose, and plasma clot systems using a variety of conditioned media. These include mitogen activated mouse spleen cells, L-cells (fibroblasts), and a myelomonocytic cell line. To these is now added a conditioned medium from BRL-3A, a rat liver cell line. Megakaryocytes show full maturation to cytoplasmic fragmentation in this system. It is suggested that colony stimulating factor for megakaryocytes may come from a variety of sources; the relationship of any of these to the physiological regulator or regulators remains quite unknown.