title: Lithium stimulated in vitro megakaryocytopoiesis.
abstract: We have investigated the effects of lithium on the proliferative potential of murine megakaryocyte stem cells (CFUMeg) in vitro and on circulating platelet levels in vivo. At optimal levels of megakaryocyte-colony stimulating factor (Meg-CSF) (10%) concentrations of 0.5, 1.0 and 3.0 meq/L augmented CFUMeg numbers. Significant increases of 133% and 125% over control levels were observed at 1.0 and 3.0 meq/L, respectively. At suboptimal concentrations of Meg-CSF (1.0%), Li effected a maximum increase of 200% over control levels at 1.0 meq/L suggesting a greater sensitivity of CFUMeg to stimulatory factors in the presence of Li. To better define the mode of action of Li, heterogenous bone marrow was separated into adherent and non-adherent cell populations and cultured in the presence of Li. Non-adherent cells cultured in the presence of 0.5, 1.0 and 3.0 meq/L Li showed significant increases in CFUMeg over non-adherent cells cultured without Li. These results suggest a direct effect of Li on CFUMeg. Cells cultured from the adherent cell population also responded to Li with enhanced CFUMeg numbers. This response may be a direct stem cell effect or an indirect effect via the production of endogenous Meg-CSF. One meq/L of Li when injected i.p., produced a thrombocytosis from days 4 through 15, with a maximum at 6 days post-Li treatment. These results suggest Li is an effective agent for stimulating megakaryocytopoiesis and has both direct and possibly indirect effects on the megakaryocyte stem cell.
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000187:drug effects; D001854:Bone Marrow Cells; D002455:Cell Division / Q000187:drug effects*; D002478:Cells, Cultured; D006412:Hematopoietic Stem Cells / Q000187:drug effects; D008094:Lithium / Q000494:pharmacology*; D008297:Male; D008533:Megakaryocytes / Q000187:drug effects*; D051379:Mice; D010976:Platelet Count
chemical_list: D008094:Lithium